From f74bce4fb8754b6277aca2dbfcc9fbe8f8d56c3c Mon Sep 17 00:00:00 2001
From: Darnell Andries <dandries@brave.com>
Date: Fri, 14 Feb 2025 16:55:49 -0800
Subject: [PATCH] Vendor Rust scraper library

---
 .../browser/document_extractor/Cargo.toml     |    3 +-
 .../rust/chromium_crates_io/Cargo.lock        |   91 +-
 .../rust/chromium_crates_io/gnrt_config.toml  |   18 +-
 .../.cargo-checksum.json                      |    0
 .../cssparser-0.34.0/.cargo_vcs_info.json     |    6 +
 .../.github/workflows/main.yml                |   81 +
 .../vendor/cssparser-0.34.0/.gitignore        |    3 +
 .../vendor/cssparser-0.34.0/Cargo.toml        |   70 +
 .../vendor/cssparser-0.34.0/Cargo.toml.orig   |   41 +
 .../LICENSE                                   |    0
 .../vendor/cssparser-0.34.0/README.md         |   57 +
 .../vendor/cssparser-0.34.0/docs/.nojekyll    |    0
 .../vendor/cssparser-0.34.0/docs/404.html     |    3 +
 .../vendor/cssparser-0.34.0/docs/index.html   |    3 +
 .../vendor/cssparser-0.34.0/src/color.rs      |  348 ++
 .../vendor/cssparser-0.34.0/src/cow_rc_str.rs |  185 +
 .../vendor/cssparser-0.34.0/src/from_bytes.rs |   64 +
 .../vendor/cssparser-0.34.0/src/lib.rs        |  108 +
 .../vendor/cssparser-0.34.0/src/macros.rs     |  204 +
 .../vendor/cssparser-0.34.0/src/nth.rs        |  145 +
 .../vendor/cssparser-0.34.0/src/parser.rs     | 1175 ++++
 .../src/rules_and_declarations.rs             |  538 ++
 .../vendor/cssparser-0.34.0/src/serializer.rs |  591 +++
 .../cssparser-0.34.0/src/size_of_tests.rs     |   52 +
 .../vendor/cssparser-0.34.0/src/tests.rs      | 1352 +++++
 .../vendor/cssparser-0.34.0/src/tokenizer.rs  | 1407 +++++
 .../cssparser-0.34.0/src/unicode_range.rs     |  179 +
 .../.cargo_vcs_info.json                      |    5 -
 .../vendor/cssparser-macros-0.6.0/lib.rs      |   39 -
 .../.cargo-checksum.json                      |    1 +
 .../.cargo_vcs_info.json                      |    6 +
 .../Cargo.toml                                |   19 +-
 .../Cargo.toml.orig                           |    4 +-
 .../vendor/cssparser-macros-0.6.1/LICENSE     |  373 ++
 .../vendor/cssparser-macros-0.6.1/lib.rs      |  190 +
 .../ego-tree-0.10.0/.cargo-checksum.json      |    1 +
 .../ego-tree-0.10.0/.cargo_vcs_info.json      |    6 +
 .../ego-tree-0.10.0/.github/dependabot.yml    |   11 +
 .../.github/workflows/test.yml                |   47 +
 .../vendor/ego-tree-0.10.0/.gitignore         |    4 +
 .../vendor/ego-tree-0.10.0/Cargo.toml         |   87 +
 .../vendor/ego-tree-0.10.0/Cargo.toml.orig    |   23 +
 .../vendor/ego-tree-0.10.0/LICENSE            |   13 +
 .../vendor/ego-tree-0.10.0/README.md          |  123 +
 .../ego-tree-0.10.0/examples/simple_tree.rs   |   28 +
 .../vendor/ego-tree-0.10.0/src/display.rs     |   89 +
 .../vendor/ego-tree-0.10.0/src/iter.rs        |  356 ++
 .../vendor/ego-tree-0.10.0/src/lib.rs         |  939 ++++
 .../vendor/ego-tree-0.10.0/src/serde.rs       |  157 +
 .../vendor/ego-tree-0.10.0/src/sort.rs        |  120 +
 .../vendor/ego-tree-0.10.0/tests/iter.rs      |  236 +
 .../vendor/ego-tree-0.10.0/tests/macro.rs     |  165 +
 .../vendor/ego-tree-0.10.0/tests/node_mut.rs  |  429 ++
 .../vendor/ego-tree-0.10.0/tests/node_ref.rs  |   83 +
 .../vendor/ego-tree-0.10.0/tests/serde.rs     |   96 +
 .../vendor/ego-tree-0.10.0/tests/sort.rs      |   91 +
 .../vendor/ego-tree-0.10.0/tests/subtree.rs   |   35 +
 .../vendor/ego-tree-0.10.0/tests/tree.rs      |  240 +
 .../getopts-0.2.21/.cargo-checksum.json       |    1 +
 .../getopts-0.2.21/.cargo_vcs_info.json       |    5 +
 .../getopts-0.2.21/.github/workflows/main.yml |   15 +
 .../vendor/getopts-0.2.21/.gitignore          |    6 +
 .../vendor/getopts-0.2.21/Cargo.toml          |   40 +
 .../vendor/getopts-0.2.21/Cargo.toml.orig     |   25 +
 .../vendor/getopts-0.2.21/LICENSE-APACHE      |  201 +
 .../vendor/getopts-0.2.21/LICENSE-MIT         |   25 +
 .../vendor/getopts-0.2.21/README.md           |   15 +
 .../vendor/getopts-0.2.21/src/lib.rs          | 1046 ++++
 .../vendor/getopts-0.2.21/src/tests/mod.rs    | 1254 +++++
 .../vendor/getopts-0.2.21/tests/smoke.rs      |    8 +
 .../phf_macros-0.11.3/.cargo-checksum.json    |    1 +
 .../phf_macros-0.11.3/.cargo_vcs_info.json    |    6 +
 .../vendor/phf_macros-0.11.3/CHANGELOG.md     |  361 ++
 .../vendor/phf_macros-0.11.3/Cargo.lock       |   97 +
 .../vendor/phf_macros-0.11.3/Cargo.toml       |   62 +
 .../vendor/phf_macros-0.11.3/Cargo.toml.orig  |   26 +
 .../vendor/phf_macros-0.11.3/LICENSE          |   20 +
 .../vendor/phf_macros-0.11.3/README.md        |  127 +
 .../vendor/phf_macros-0.11.3/src/lib.rs       |  338 ++
 .../scraper-0.22.0/.cargo-checksum.json       |    1 +
 .../scraper-0.22.0/.cargo_vcs_info.json       |    6 +
 .../vendor/scraper-0.22.0/Cargo.lock          |  626 +++
 .../vendor/scraper-0.22.0/Cargo.toml          |   84 +
 .../vendor/scraper-0.22.0/Cargo.toml.orig     |   38 +
 .../vendor/scraper-0.22.0/LICENSE             |    1 +
 .../vendor/scraper-0.22.0/README.md           |    1 +
 .../scraper-0.22.0/examples/document.rs       |   28 +
 .../scraper-0.22.0/examples/fragment.rs       |   28 +
 .../vendor/scraper-0.22.0/scraper.1           |   72 +
 .../scraper-0.22.0/src/element_ref/element.rs |  212 +
 .../scraper-0.22.0/src/element_ref/mod.rs     |  236 +
 .../src/element_ref/serializable.rs           |   15 +
 .../vendor/scraper-0.22.0/src/error.rs        |  119 +
 .../vendor/scraper-0.22.0/src/error/utils.rs  |   91 +
 .../vendor/scraper-0.22.0/src/html/mod.rs     |  269 +
 .../scraper-0.22.0/src/html/serializable.rs   |   27 +
 .../scraper-0.22.0/src/html/tree_sink.rs      |  297 ++
 .../vendor/scraper-0.22.0/src/lib.rs          |  182 +
 .../vendor/scraper-0.22.0/src/main.rs         |  132 +
 .../vendor/scraper-0.22.0/src/node.rs         |  388 ++
 .../scraper-0.22.0/src/node/serializable.rs   |   52 +
 .../vendor/scraper-0.22.0/src/selectable.rs   |   70 +
 .../vendor/scraper-0.22.0/src/selector.rs     |  257 +
 .../vendor/scraper-0.22.0/src/test.rs         |   46 +
 .../selectors-0.26.0/.cargo-checksum.json     |    1 +
 .../selectors-0.26.0/.cargo_vcs_info.json     |    6 +
 .../vendor/selectors-0.26.0/CHANGES.md        |    1 +
 .../vendor/selectors-0.26.0/Cargo.toml        |   88 +
 .../vendor/selectors-0.26.0/Cargo.toml.orig   |   37 +
 .../vendor/selectors-0.26.0/README.md         |   25 +
 .../vendor/selectors-0.26.0/attr.rs           |  196 +
 .../vendor/selectors-0.26.0/bloom.rs          |  422 ++
 .../vendor/selectors-0.26.0/build.rs          |   77 +
 .../vendor/selectors-0.26.0/builder.rs        |  425 ++
 .../vendor/selectors-0.26.0/context.rs        |  466 ++
 .../vendor/selectors-0.26.0/kleene_value.rs   |  134 +
 .../vendor/selectors-0.26.0/lib.rs            |   23 +
 .../vendor/selectors-0.26.0/matching.rs       | 1516 ++++++
 .../selectors-0.26.0/nth_index_cache.rs       |  102 +
 .../vendor/selectors-0.26.0/parser.rs         | 4711 +++++++++++++++++
 .../relative_selector/cache.rs                |   81 +
 .../relative_selector/filter.rs               |  159 +
 .../selectors-0.26.0/relative_selector/mod.rs |    6 +
 .../vendor/selectors-0.26.0/sink.rs           |   31 +
 .../vendor/selectors-0.26.0/tree.rs           |  181 +
 .../vendor/selectors-0.26.0/visitor.rs        |  137 +
 .../servo_arc-0.4.0/.cargo-checksum.json      |    1 +
 .../servo_arc-0.4.0/.cargo_vcs_info.json      |    6 +
 .../vendor/servo_arc-0.4.0/Cargo.toml         |   44 +
 .../vendor/servo_arc-0.4.0/Cargo.toml.orig    |   21 +
 .../vendor/servo_arc-0.4.0/LICENSE-APACHE     |  201 +
 .../vendor/servo_arc-0.4.0/LICENSE-MIT        |   23 +
 .../vendor/servo_arc-0.4.0/lib.rs             | 1198 +++++
 third_party/rust/cssparser/v0_27/BUILD.gn     |    8 +-
 third_party/rust/cssparser/v0_28/BUILD.gn     |    8 +-
 third_party/rust/cssparser/v0_34/BUILD.gn     |   61 +
 .../rust/cssparser/v0_34/README.chromium      |   10 +
 .../rust/cssparser_macros/v0_6/BUILD.gn       |   12 +-
 .../cssparser_macros/v0_6/README.chromium     |    6 +-
 third_party/rust/ego_tree/v0_10/BUILD.gn      |   40 +
 .../rust/ego_tree/v0_10/README.chromium       |   10 +
 third_party/rust/getopts/v0_2/BUILD.gn        |   38 +
 third_party/rust/getopts/v0_2/README.chromium |   11 +
 third_party/rust/phf/v0_11/BUILD.gn           |   11 +-
 third_party/rust/phf_macros/v0_11/BUILD.gn    |   44 +
 .../rust/phf_macros/v0_11/README.chromium     |   10 +
 third_party/rust/phf_macros/v0_8/BUILD.gn     |    3 +
 third_party/rust/scraper/v0_22/BUILD.gn       |   64 +
 .../rust/scraper/v0_22/README.chromium        |   10 +
 third_party/rust/selectors/v0_26/BUILD.gn     |   75 +
 .../rust/selectors/v0_26/README.chromium      |   10 +
 third_party/rust/servo_arc/v0_4/BUILD.gn      |   40 +
 .../rust/servo_arc/v0_4/README.chromium       |   10 +
 third_party/rust/unicode_width/v0_1/BUILD.gn  |    8 +
 .../rust/unicode_width/v0_1/README.chromium   |   11 +
 155 files changed, 28436 insertions(+), 80 deletions(-)
 rename third_party/rust/chromium_crates_io/vendor/{cssparser-macros-0.6.0 => cssparser-0.34.0}/.cargo-checksum.json (100%)
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.github/workflows/main.yml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.gitignore
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml.orig
 rename third_party/rust/chromium_crates_io/vendor/{cssparser-macros-0.6.0 => cssparser-0.34.0}/LICENSE (100%)
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/.nojekyll
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/404.html
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/index.html
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/color.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/cow_rc_str.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/from_bytes.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/macros.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/nth.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/parser.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/rules_and_declarations.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/serializer.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/size_of_tests.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tests.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tokenizer.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/unicode_range.rs
 delete mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo_vcs_info.json
 delete mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo_vcs_info.json
 rename third_party/rust/chromium_crates_io/vendor/{cssparser-macros-0.6.0 => cssparser-macros-0.6.1}/Cargo.toml (63%)
 rename third_party/rust/chromium_crates_io/vendor/{cssparser-macros-0.6.0 => cssparser-macros-0.6.1}/Cargo.toml.orig (81%)
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/LICENSE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/dependabot.yml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/workflows/test.yml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.gitignore
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/LICENSE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/examples/simple_tree.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/display.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/iter.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/serde.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/sort.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/iter.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/macro.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_mut.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_ref.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/serde.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/sort.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/subtree.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/tree.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.github/workflows/main.yml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.gitignore
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-APACHE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-MIT
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/tests/mod.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/tests/smoke.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/CHANGELOG.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.lock
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/LICENSE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.lock
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/LICENSE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/document.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/fragment.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/scraper.1
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/element.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/mod.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/serializable.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error/utils.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/mod.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/serializable.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/tree_sink.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/main.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node/serializable.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selectable.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selector.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/test.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/CHANGES.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/README.md
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/attr.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/bloom.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/builder.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/context.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/kleene_value.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/matching.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/nth_index_cache.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/parser.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/cache.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/filter.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/mod.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/sink.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/tree.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/visitor.rs
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo-checksum.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo_vcs_info.json
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml.orig
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-APACHE
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-MIT
 create mode 100644 third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs
 create mode 100644 third_party/rust/cssparser/v0_34/BUILD.gn
 create mode 100644 third_party/rust/cssparser/v0_34/README.chromium
 create mode 100644 third_party/rust/ego_tree/v0_10/BUILD.gn
 create mode 100644 third_party/rust/ego_tree/v0_10/README.chromium
 create mode 100644 third_party/rust/getopts/v0_2/BUILD.gn
 create mode 100644 third_party/rust/getopts/v0_2/README.chromium
 create mode 100644 third_party/rust/phf_macros/v0_11/BUILD.gn
 create mode 100644 third_party/rust/phf_macros/v0_11/README.chromium
 create mode 100644 third_party/rust/scraper/v0_22/BUILD.gn
 create mode 100644 third_party/rust/scraper/v0_22/README.chromium
 create mode 100644 third_party/rust/selectors/v0_26/BUILD.gn
 create mode 100644 third_party/rust/selectors/v0_26/README.chromium
 create mode 100644 third_party/rust/servo_arc/v0_4/BUILD.gn
 create mode 100644 third_party/rust/servo_arc/v0_4/README.chromium
 create mode 100644 third_party/rust/unicode_width/v0_1/BUILD.gn
 create mode 100644 third_party/rust/unicode_width/v0_1/README.chromium

diff --git a/components/web_discovery/browser/document_extractor/Cargo.toml b/components/web_discovery/browser/document_extractor/Cargo.toml
index 3211320d6dcc..efb3afae020b 100644
--- a/components/web_discovery/browser/document_extractor/Cargo.toml
+++ b/components/web_discovery/browser/document_extractor/Cargo.toml
@@ -7,8 +7,7 @@ license = "MPL-2.0"
 
 [dependencies]
 cxx = "1"
-kuchikiki = "0.8.7-speedreader"
-html5ever = "0.29.1"
+scraper = "0.22"
 
 [lib]
 name = "document_extractor_cxx"
diff --git a/third_party/rust/chromium_crates_io/Cargo.lock b/third_party/rust/chromium_crates_io/Cargo.lock
index bbf6dee5e77b..9a6ceecb4a36 100644
--- a/third_party/rust/chromium_crates_io/Cargo.lock
+++ b/third_party/rust/chromium_crates_io/Cargo.lock
@@ -533,13 +533,25 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "cssparser"
+version = "0.34.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cssparser-macros",
+ "dtoa-short",
+ "itoa 1.0.14",
+ "phf 0.11.3",
+ "smallvec",
+]
+
 [[package]]
 name = "cssparser-macros"
-version = "0.6.0"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "quote",
- "syn 1.0.109",
+ "syn 2.0.96",
 ]
 
 [[package]]
@@ -672,8 +684,7 @@ name = "document-extractor"
 version = "0.1.0"
 dependencies = [
  "cxx",
- "html5ever",
- "kuchikiki",
+ "scraper",
 ]
 
 [[package]]
@@ -689,6 +700,11 @@ dependencies = [
  "dtoa",
 ]
 
+[[package]]
+name = "ego-tree"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "either"
 version = "1.8.1"
@@ -990,6 +1006,14 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getopts"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-width",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.16"
@@ -1643,7 +1667,7 @@ name = "phf"
 version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "phf_macros",
+ "phf_macros 0.8.0",
  "phf_shared 0.8.0",
  "proc-macro-hack",
 ]
@@ -1653,6 +1677,7 @@ name = "phf"
 version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "phf_macros 0.11.3",
  "phf_shared 0.11.3",
 ]
 
@@ -1714,6 +1739,18 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "phf_macros"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "phf_generator 0.11.3",
+ "phf_shared 0.11.3",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.96",
+]
+
 [[package]]
 name = "phf_shared"
 version = "0.8.0"
@@ -2024,6 +2061,20 @@ name = "scopeguard"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "scraper"
+version = "0.22.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cssparser 0.34.0",
+ "ego-tree",
+ "getopts",
+ "html5ever",
+ "precomputed-hash",
+ "selectors 0.26.0",
+ "tendril",
+]
+
 [[package]]
 name = "seahash"
 version = "3.0.7"
@@ -2043,7 +2094,7 @@ dependencies = [
  "phf 0.8.0",
  "phf_codegen 0.8.0",
  "precomputed-hash",
- "servo_arc",
+ "servo_arc 0.1.1",
  "smallvec",
  "thin-slice",
 ]
@@ -2061,7 +2112,25 @@ dependencies = [
  "phf 0.8.0",
  "phf_codegen 0.8.0",
  "precomputed-hash",
- "servo_arc",
+ "servo_arc 0.1.1",
+ "smallvec",
+]
+
+[[package]]
+name = "selectors"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 2.8.0",
+ "cssparser 0.34.0",
+ "derive_more",
+ "fxhash",
+ "log",
+ "new_debug_unreachable",
+ "phf 0.11.3",
+ "phf_codegen 0.11.3",
+ "precomputed-hash",
+ "servo_arc 0.4.0",
  "smallvec",
 ]
 
@@ -2152,6 +2221,14 @@ dependencies = [
  "stable_deref_trait",
 ]
 
+[[package]]
+name = "servo_arc"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "sha2"
 version = "0.9.9"
diff --git a/third_party/rust/chromium_crates_io/gnrt_config.toml b/third_party/rust/chromium_crates_io/gnrt_config.toml
index 67cb0047ffc7..344938233a1c 100644
--- a/third_party/rust/chromium_crates_io/gnrt_config.toml
+++ b/third_party/rust/chromium_crates_io/gnrt_config.toml
@@ -153,9 +153,13 @@ if (is_apple && target_cpu == "arm64") {
 build_script_outputs = [ "lib.rs" ]
 
 [crate.cssparser]
-build_script_outputs = [ "tokenizer.rs" ]
-extra_build_script_src_roots = [ "../build" ]
 license_files = ['LICENSE']
+extra_kv = { raw_gn = '''
+if (epoch == "0.28" || epoch == "0.27") {
+    build_script_inputs = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-" + cargo_pkg_version + "/build/match_byte.rs" ]
+    build_script_outputs = [ "tokenizer.rs" ]
+  }
+''' }
 
 [crate.cssparser-macros]
 license_files = ['LICENSE']
@@ -283,6 +287,13 @@ license_files = ['LICENSE-Apache']
 [crate.num-traits]
 extra_kv = { rustflags = [ "--cfg", "has_i128", "--cfg", "has_to_int_unchecked", "--cfg", "has_reverse_bits", "--cfg", "has_leading_trailing_ones", "--cfg", "has_int_assignop_ref", "--cfg", "has_div_euclid", "--cfg", "has_copysign" ] }
 
+[crate.phf_macros]
+extra_kv = { raw_gn = '''
+if (epoch == "0.11") {
+  output_name = "phf_macros_v0_11"
+}
+''' }
+
 [crate.powerfmt]
 license_files = ['LICENSE-Apache']
 
@@ -374,6 +385,9 @@ extra_kv = { rustenv = [ "TYPENUM_BUILD_CONSTS=\" + rebase_path(target_gen_dir)
 [crate.uint]
 license_files = ['../../../../../common/licenses/Apache-2.0']
 
+[crate.unicode-width]
+license_files = ['../../../../../common/licenses/Apache-2.0']
+
 [crate.wasi]
 license_files = ['../../../../../common/licenses/Apache-2.0']
 
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo-checksum.json
similarity index 100%
rename from third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo-checksum.json
rename to third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo-checksum.json
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo_vcs_info.json
new file mode 100644
index 000000000000..7e6f5be881e6
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "5dc6d916a73159745e1fc1dd1f745e05d3130b0f"
+  },
+  "path_in_vcs": ""
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.github/workflows/main.yml b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.github/workflows/main.yml
new file mode 100644
index 000000000000..b08ddef76de7
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.github/workflows/main.yml
@@ -0,0 +1,81 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+  merge_group:
+    types: [checks_requested]
+
+jobs:
+  linux-ci:
+    name: Linux
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        toolchain:
+          - nightly
+          - beta
+          - stable
+          - 1.63.0
+        features:
+          -
+          - --features dummy_match_byte
+        include:
+          - toolchain: nightly
+            features: --features bench
+          - toolchain: nightly
+            features: --features bench,dummy_match_byte
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.toolchain }}
+          override: true
+          components: rustfmt, clippy, ${{ matrix.toolchain == 'nightly' && 'miri,rust-src' || '' }}
+
+      - name: Cargo format & lint
+        run: cargo fmt --check && cargo clippy -- -Dwarnings
+
+      - name: Cargo build
+        run: cargo build ${{ matrix.features }}
+
+      - name: Cargo doc
+        run: cargo doc ${{ matrix.features }}
+
+      - name: Cargo test
+        run: cargo test ${{ matrix.features }}
+
+      - name: macros build
+        run: cargo build
+        working-directory: macros
+
+      - name: Color build
+        run: cargo build
+        working-directory: color
+
+      - name: Color test
+        run: cargo test
+        working-directory: color
+
+      - name: Cargo miri test
+        if: "matrix.toolchain == 'nightly'"
+        run: cargo miri test --features skip_long_tests ${{ matrix.features }}
+
+  build_result:
+    name: Result
+    runs-on: ubuntu-latest
+    needs:
+      - "linux-ci"
+
+    steps:
+      - name: Mark the job as successful
+        run: exit 0
+        if: success()
+      - name: Mark the job as unsuccessful
+        run: exit 1
+        if: "!success()"
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.gitignore b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.gitignore
new file mode 100644
index 000000000000..0b837eae334b
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/.gitignore
@@ -0,0 +1,3 @@
+target
+/Cargo.lock
+/.cargo/config
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml
new file mode 100644
index 000000000000..bceceea9d289
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml
@@ -0,0 +1,70 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2018"
+rust-version = "1.63"
+name = "cssparser"
+version = "0.34.0"
+authors = ["Simon Sapin <simon.sapin@exyr.org>"]
+exclude = [
+    "src/css-parsing-tests/**",
+    "src/big-data-url.css",
+]
+description = "Rust implementation of CSS Syntax Level 3"
+documentation = "https://docs.rs/cssparser/"
+readme = "README.md"
+keywords = [
+    "css",
+    "syntax",
+    "parser",
+]
+license = "MPL-2.0"
+repository = "https://github.com/servo/rust-cssparser"
+
+[profile.profiling]
+debug = 2
+inherits = "release"
+
+[dependencies.cssparser-macros]
+version = "0.6.1"
+
+[dependencies.dtoa-short]
+version = "0.3"
+
+[dependencies.itoa]
+version = "1.0"
+
+[dependencies.phf]
+version = "0.11.2"
+features = ["macros"]
+
+[dependencies.serde]
+version = "1.0"
+features = ["derive"]
+optional = true
+
+[dependencies.smallvec]
+version = "1.0"
+
+[dev-dependencies.difference]
+version = "2.0"
+
+[dev-dependencies.encoding_rs]
+version = "0.8"
+
+[dev-dependencies.serde_json]
+version = "1.0.25"
+
+[features]
+bench = []
+dummy_match_byte = []
+skip_long_tests = []
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml.orig
new file mode 100644
index 000000000000..f783f19ffc9e
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/Cargo.toml.orig
@@ -0,0 +1,41 @@
+[package]
+name = "cssparser"
+version = "0.34.0"
+authors = ["Simon Sapin <simon.sapin@exyr.org>"]
+
+description = "Rust implementation of CSS Syntax Level 3"
+documentation = "https://docs.rs/cssparser/"
+repository = "https://github.com/servo/rust-cssparser"
+readme = "README.md"
+keywords = ["css", "syntax", "parser"]
+license = "MPL-2.0"
+edition = "2018"
+rust-version = "1.63"
+
+exclude = ["src/css-parsing-tests/**", "src/big-data-url.css"]
+
+[dev-dependencies]
+serde_json = "1.0.25"
+difference = "2.0"
+encoding_rs = "0.8"
+
+[dependencies]
+cssparser-macros = { path = "./macros", version = "0.6.1" }
+dtoa-short = "0.3"
+itoa = "1.0"
+phf = { version = "0.11.2", features = ["macros"] }
+serde = { version = "1.0", features = ["derive"], optional = true }
+smallvec = "1.0"
+
+[profile.profiling]
+inherits = "release"
+debug = true
+
+[features]
+bench = []
+dummy_match_byte = []
+# Useful for skipping tests when execution is slow, e.g., under miri
+skip_long_tests = []
+
+[workspace]
+members = [".", "./macros", "./color"]
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/LICENSE b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/LICENSE
similarity index 100%
rename from third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/LICENSE
rename to third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/LICENSE
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/README.md b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/README.md
new file mode 100644
index 000000000000..d9ca4ada84b1
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/README.md
@@ -0,0 +1,57 @@
+rust-cssparser
+==============
+
+[![Build Status](https://github.com/servo/rust-cssparser/actions/workflows/main.yml/badge.svg)](https://github.com/servo/rust-cssparser/actions)
+
+[Documentation](https://docs.rs/cssparser)
+
+Rust implementation of
+[CSS Syntax Module Level 3](https://drafts.csswg.org/css-syntax/)
+
+
+Overview
+--------
+
+Parsing CSS involves a series of steps:
+
+* When parsing from bytes,
+  (e.g. reading a file or fetching an URL from the network,)
+  detect the character encoding
+  (based on a `Content-Type` HTTP header, an `@charset` rule, a BOM, etc.)
+  and decode to Unicode text.
+
+  rust-cssparser does not do this yet and just assumes UTF-8.
+
+  This step is skipped when parsing from Unicode, e.g. in an HTML `<style>` element.
+
+* Tokenization, a.k.a. lexing.
+  The input, a stream of Unicode text, is transformed into a stream of *tokens*.
+  Tokenization never fails, although the output may contain *error tokens*.
+
+* This flat stream of tokens is then transformed into a tree of *component values*,
+  which are either *preserved tokens*,
+  or blocks/functions (`{ … }`, `[ … ]`, `( … )`, `foo( … )`)
+  that contain more component values.
+
+  rust-cssparser does this at the same time as tokenization:
+  raw tokens are never materialized, you only get component values.
+
+* Component values can then be parsed into generic rules or declarations.
+  The header and body of rules as well as the value of declarations
+  are still just lists of component values at this point.
+  See [the `Token` enum](src/tokenizer.rs) for the data structure.
+
+* The last step of a full CSS parser is
+  parsing the remaining component values
+  into [Selectors](https://drafts.csswg.org/selectors/),
+  specific CSS properties, etc.
+
+  By design, rust-cssparser does not do this last step
+  which depends a lot on what you want to do:
+  which properties you want to support, what you want to do with selectors, etc.
+
+  It does however provide some helper functions to parse [CSS colors](src/color.rs)
+  and [An+B](src/nth.rs) (the argument to `:nth-child()` and related selectors.
+
+  See [Servo’s `style` crate](https://github.com/servo/stylo/tree/main/style)
+  for an example of a parser based on rust-cssparser.
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/.nojekyll b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/.nojekyll
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/404.html b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/404.html
new file mode 100644
index 000000000000..bf70be151dbd
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/404.html
@@ -0,0 +1,3 @@
+<meta http-equiv="refresh" content="0; url=https://docs.rs/cssparser/">
+<link rel="canonical" href="https://docs.rs/cssparser/">
+<a href="https://docs.rs/cssparser/">Moved to docs.rs</a>
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/index.html b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/index.html
new file mode 100644
index 000000000000..bf70be151dbd
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/docs/index.html
@@ -0,0 +1,3 @@
+<meta http-equiv="refresh" content="0; url=https://docs.rs/cssparser/">
+<link rel="canonical" href="https://docs.rs/cssparser/">
+<a href="https://docs.rs/cssparser/">Moved to docs.rs</a>
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/color.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/color.rs
new file mode 100644
index 000000000000..978936e01a02
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/color.rs
@@ -0,0 +1,348 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! General color-parsing utilities, independent on the specific color storage and parsing
+//! implementation.
+//!
+//! For a more complete css-color implementation take a look at cssparser-color crate, or at
+//! Gecko's color module.
+
+// Allow text like <color> in docs.
+#![allow(rustdoc::invalid_html_tags)]
+
+/// The opaque alpha value of 1.0.
+pub const OPAQUE: f32 = 1.0;
+
+use crate::{BasicParseError, Parser, ToCss, Token};
+use std::fmt;
+
+/// Clamp a 0..1 number to a 0..255 range to u8.
+///
+/// Whilst scaling by 256 and flooring would provide
+/// an equal distribution of integers to percentage inputs,
+/// this is not what Gecko does so we instead multiply by 255
+/// and round (adding 0.5 and flooring is equivalent to rounding)
+///
+/// Chrome does something similar for the alpha value, but not
+/// the rgb values.
+///
+/// See <https://bugzilla.mozilla.org/show_bug.cgi?id=1340484>
+///
+/// Clamping to 256 and rounding after would let 1.0 map to 256, and
+/// `256.0_f32 as u8` is undefined behavior:
+///
+/// <https://github.com/rust-lang/rust/issues/10184>
+#[inline]
+pub fn clamp_unit_f32(val: f32) -> u8 {
+    clamp_floor_256_f32(val * 255.)
+}
+
+/// Round and clamp a single number to a u8.
+#[inline]
+pub fn clamp_floor_256_f32(val: f32) -> u8 {
+    val.round().clamp(0., 255.) as u8
+}
+
+/// Serialize the alpha copmonent of a color according to the specification.
+/// <https://drafts.csswg.org/css-color-4/#serializing-alpha-values>
+#[inline]
+pub fn serialize_color_alpha(
+    dest: &mut impl fmt::Write,
+    alpha: Option<f32>,
+    legacy_syntax: bool,
+) -> fmt::Result {
+    let alpha = match alpha {
+        None => return dest.write_str(" / none"),
+        Some(a) => a,
+    };
+
+    // If the alpha component is full opaque, don't emit the alpha value in CSS.
+    if alpha == OPAQUE {
+        return Ok(());
+    }
+
+    dest.write_str(if legacy_syntax { ", " } else { " / " })?;
+
+    // Try first with two decimal places, then with three.
+    let mut rounded_alpha = (alpha * 100.).round() / 100.;
+    if clamp_unit_f32(rounded_alpha) != clamp_unit_f32(alpha) {
+        rounded_alpha = (alpha * 1000.).round() / 1000.;
+    }
+
+    rounded_alpha.to_css(dest)
+}
+
+/// A Predefined color space specified in:
+/// <https://drafts.csswg.org/css-color-4/#predefined>
+#[derive(Clone, Copy, Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(tag = "type"))]
+pub enum PredefinedColorSpace {
+    /// <https://drafts.csswg.org/css-color-4/#predefined-sRGB>
+    Srgb,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-sRGB-linear>
+    SrgbLinear,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-display-p3>
+    DisplayP3,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-a98-rgb>
+    A98Rgb,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-prophoto-rgb>
+    ProphotoRgb,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-rec2020>
+    Rec2020,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-xyz>
+    XyzD50,
+    /// <https://drafts.csswg.org/css-color-4/#predefined-xyz>
+    XyzD65,
+}
+
+impl PredefinedColorSpace {
+    /// Parse a PredefinedColorSpace from the given input.
+    pub fn parse<'i>(input: &mut Parser<'i, '_>) -> Result<Self, BasicParseError<'i>> {
+        let location = input.current_source_location();
+
+        let ident = input.expect_ident()?;
+        Ok(match_ignore_ascii_case! { ident,
+            "srgb" => Self::Srgb,
+            "srgb-linear" => Self::SrgbLinear,
+            "display-p3" => Self::DisplayP3,
+            "a98-rgb" => Self::A98Rgb,
+            "prophoto-rgb" => Self::ProphotoRgb,
+            "rec2020" => Self::Rec2020,
+            "xyz-d50" => Self::XyzD50,
+            "xyz" | "xyz-d65" => Self::XyzD65,
+            _ => return Err(location.new_basic_unexpected_token_error(Token::Ident(ident.clone()))),
+        })
+    }
+}
+
+impl ToCss for PredefinedColorSpace {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        dest.write_str(match self {
+            Self::Srgb => "srgb",
+            Self::SrgbLinear => "srgb-linear",
+            Self::DisplayP3 => "display-p3",
+            Self::A98Rgb => "a98-rgb",
+            Self::ProphotoRgb => "prophoto-rgb",
+            Self::Rec2020 => "rec2020",
+            Self::XyzD50 => "xyz-d50",
+            Self::XyzD65 => "xyz-d65",
+        })
+    }
+}
+
+/// Parse a color hash, without the leading '#' character.
+#[allow(clippy::result_unit_err)]
+#[inline]
+pub fn parse_hash_color(value: &[u8]) -> Result<(u8, u8, u8, f32), ()> {
+    Ok(match value.len() {
+        8 => (
+            from_hex(value[0])? * 16 + from_hex(value[1])?,
+            from_hex(value[2])? * 16 + from_hex(value[3])?,
+            from_hex(value[4])? * 16 + from_hex(value[5])?,
+            (from_hex(value[6])? * 16 + from_hex(value[7])?) as f32 / 255.0,
+        ),
+        6 => (
+            from_hex(value[0])? * 16 + from_hex(value[1])?,
+            from_hex(value[2])? * 16 + from_hex(value[3])?,
+            from_hex(value[4])? * 16 + from_hex(value[5])?,
+            OPAQUE,
+        ),
+        4 => (
+            from_hex(value[0])? * 17,
+            from_hex(value[1])? * 17,
+            from_hex(value[2])? * 17,
+            (from_hex(value[3])? * 17) as f32 / 255.0,
+        ),
+        3 => (
+            from_hex(value[0])? * 17,
+            from_hex(value[1])? * 17,
+            from_hex(value[2])? * 17,
+            OPAQUE,
+        ),
+        _ => return Err(()),
+    })
+}
+
+ascii_case_insensitive_phf_map! {
+    named_colors -> (u8, u8, u8) = {
+        "black" => (0, 0, 0),
+        "silver" => (192, 192, 192),
+        "gray" => (128, 128, 128),
+        "white" => (255, 255, 255),
+        "maroon" => (128, 0, 0),
+        "red" => (255, 0, 0),
+        "purple" => (128, 0, 128),
+        "fuchsia" => (255, 0, 255),
+        "green" => (0, 128, 0),
+        "lime" => (0, 255, 0),
+        "olive" => (128, 128, 0),
+        "yellow" => (255, 255, 0),
+        "navy" => (0, 0, 128),
+        "blue" => (0, 0, 255),
+        "teal" => (0, 128, 128),
+        "aqua" => (0, 255, 255),
+
+        "aliceblue" => (240, 248, 255),
+        "antiquewhite" => (250, 235, 215),
+        "aquamarine" => (127, 255, 212),
+        "azure" => (240, 255, 255),
+        "beige" => (245, 245, 220),
+        "bisque" => (255, 228, 196),
+        "blanchedalmond" => (255, 235, 205),
+        "blueviolet" => (138, 43, 226),
+        "brown" => (165, 42, 42),
+        "burlywood" => (222, 184, 135),
+        "cadetblue" => (95, 158, 160),
+        "chartreuse" => (127, 255, 0),
+        "chocolate" => (210, 105, 30),
+        "coral" => (255, 127, 80),
+        "cornflowerblue" => (100, 149, 237),
+        "cornsilk" => (255, 248, 220),
+        "crimson" => (220, 20, 60),
+        "cyan" => (0, 255, 255),
+        "darkblue" => (0, 0, 139),
+        "darkcyan" => (0, 139, 139),
+        "darkgoldenrod" => (184, 134, 11),
+        "darkgray" => (169, 169, 169),
+        "darkgreen" => (0, 100, 0),
+        "darkgrey" => (169, 169, 169),
+        "darkkhaki" => (189, 183, 107),
+        "darkmagenta" => (139, 0, 139),
+        "darkolivegreen" => (85, 107, 47),
+        "darkorange" => (255, 140, 0),
+        "darkorchid" => (153, 50, 204),
+        "darkred" => (139, 0, 0),
+        "darksalmon" => (233, 150, 122),
+        "darkseagreen" => (143, 188, 143),
+        "darkslateblue" => (72, 61, 139),
+        "darkslategray" => (47, 79, 79),
+        "darkslategrey" => (47, 79, 79),
+        "darkturquoise" => (0, 206, 209),
+        "darkviolet" => (148, 0, 211),
+        "deeppink" => (255, 20, 147),
+        "deepskyblue" => (0, 191, 255),
+        "dimgray" => (105, 105, 105),
+        "dimgrey" => (105, 105, 105),
+        "dodgerblue" => (30, 144, 255),
+        "firebrick" => (178, 34, 34),
+        "floralwhite" => (255, 250, 240),
+        "forestgreen" => (34, 139, 34),
+        "gainsboro" => (220, 220, 220),
+        "ghostwhite" => (248, 248, 255),
+        "gold" => (255, 215, 0),
+        "goldenrod" => (218, 165, 32),
+        "greenyellow" => (173, 255, 47),
+        "grey" => (128, 128, 128),
+        "honeydew" => (240, 255, 240),
+        "hotpink" => (255, 105, 180),
+        "indianred" => (205, 92, 92),
+        "indigo" => (75, 0, 130),
+        "ivory" => (255, 255, 240),
+        "khaki" => (240, 230, 140),
+        "lavender" => (230, 230, 250),
+        "lavenderblush" => (255, 240, 245),
+        "lawngreen" => (124, 252, 0),
+        "lemonchiffon" => (255, 250, 205),
+        "lightblue" => (173, 216, 230),
+        "lightcoral" => (240, 128, 128),
+        "lightcyan" => (224, 255, 255),
+        "lightgoldenrodyellow" => (250, 250, 210),
+        "lightgray" => (211, 211, 211),
+        "lightgreen" => (144, 238, 144),
+        "lightgrey" => (211, 211, 211),
+        "lightpink" => (255, 182, 193),
+        "lightsalmon" => (255, 160, 122),
+        "lightseagreen" => (32, 178, 170),
+        "lightskyblue" => (135, 206, 250),
+        "lightslategray" => (119, 136, 153),
+        "lightslategrey" => (119, 136, 153),
+        "lightsteelblue" => (176, 196, 222),
+        "lightyellow" => (255, 255, 224),
+        "limegreen" => (50, 205, 50),
+        "linen" => (250, 240, 230),
+        "magenta" => (255, 0, 255),
+        "mediumaquamarine" => (102, 205, 170),
+        "mediumblue" => (0, 0, 205),
+        "mediumorchid" => (186, 85, 211),
+        "mediumpurple" => (147, 112, 219),
+        "mediumseagreen" => (60, 179, 113),
+        "mediumslateblue" => (123, 104, 238),
+        "mediumspringgreen" => (0, 250, 154),
+        "mediumturquoise" => (72, 209, 204),
+        "mediumvioletred" => (199, 21, 133),
+        "midnightblue" => (25, 25, 112),
+        "mintcream" => (245, 255, 250),
+        "mistyrose" => (255, 228, 225),
+        "moccasin" => (255, 228, 181),
+        "navajowhite" => (255, 222, 173),
+        "oldlace" => (253, 245, 230),
+        "olivedrab" => (107, 142, 35),
+        "orange" => (255, 165, 0),
+        "orangered" => (255, 69, 0),
+        "orchid" => (218, 112, 214),
+        "palegoldenrod" => (238, 232, 170),
+        "palegreen" => (152, 251, 152),
+        "paleturquoise" => (175, 238, 238),
+        "palevioletred" => (219, 112, 147),
+        "papayawhip" => (255, 239, 213),
+        "peachpuff" => (255, 218, 185),
+        "peru" => (205, 133, 63),
+        "pink" => (255, 192, 203),
+        "plum" => (221, 160, 221),
+        "powderblue" => (176, 224, 230),
+        "rebeccapurple" => (102, 51, 153),
+        "rosybrown" => (188, 143, 143),
+        "royalblue" => (65, 105, 225),
+        "saddlebrown" => (139, 69, 19),
+        "salmon" => (250, 128, 114),
+        "sandybrown" => (244, 164, 96),
+        "seagreen" => (46, 139, 87),
+        "seashell" => (255, 245, 238),
+        "sienna" => (160, 82, 45),
+        "skyblue" => (135, 206, 235),
+        "slateblue" => (106, 90, 205),
+        "slategray" => (112, 128, 144),
+        "slategrey" => (112, 128, 144),
+        "snow" => (255, 250, 250),
+        "springgreen" => (0, 255, 127),
+        "steelblue" => (70, 130, 180),
+        "tan" => (210, 180, 140),
+        "thistle" => (216, 191, 216),
+        "tomato" => (255, 99, 71),
+        "turquoise" => (64, 224, 208),
+        "violet" => (238, 130, 238),
+        "wheat" => (245, 222, 179),
+        "whitesmoke" => (245, 245, 245),
+        "yellowgreen" => (154, 205, 50),
+    }
+}
+
+/// Returns the named color with the given name.
+/// <https://drafts.csswg.org/css-color-4/#typedef-named-color>
+#[allow(clippy::result_unit_err)]
+#[inline]
+pub fn parse_named_color(ident: &str) -> Result<(u8, u8, u8), ()> {
+    named_colors::get(ident).copied().ok_or(())
+}
+
+/// Returns an iterator over all named CSS colors.
+/// <https://drafts.csswg.org/css-color-4/#typedef-named-color>
+#[inline]
+pub fn all_named_colors() -> impl Iterator<Item = (&'static str, (u8, u8, u8))> {
+    named_colors::entries().map(|(k, v)| (*k, *v))
+}
+
+#[inline]
+fn from_hex(c: u8) -> Result<u8, ()> {
+    match c {
+        b'0'..=b'9' => Ok(c - b'0'),
+        b'a'..=b'f' => Ok(c - b'a' + 10),
+        b'A'..=b'F' => Ok(c - b'A' + 10),
+        _ => Err(()),
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/cow_rc_str.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/cow_rc_str.rs
new file mode 100644
index 000000000000..2650848111c1
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/cow_rc_str.rs
@@ -0,0 +1,185 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::borrow::{Borrow, Cow};
+use std::rc::Rc;
+use std::{cmp, fmt, hash, marker, mem, ops, ptr, slice, str};
+
+/// A string that is either shared (heap-allocated and reference-counted) or borrowed.
+///
+/// Equivalent to `enum { Borrowed(&'a str), Shared(Rc<String>) }`, but stored more compactly.
+///
+/// * If `borrowed_len_or_max == usize::MAX`, then `ptr` represents `NonZero<*const String>`
+///   from `Rc::into_raw`.
+///   The lifetime parameter `'a` is irrelevant in this case.
+///
+/// * Otherwise, `ptr` represents the `NonZero<*const u8>` data component of `&'a str`,
+///   and `borrowed_len_or_max` its length.
+pub struct CowRcStr<'a> {
+    ptr: ptr::NonNull<()>,
+    borrowed_len_or_max: usize,
+
+    phantom: marker::PhantomData<Result<&'a str, Rc<String>>>,
+}
+
+fn _static_assert_same_size() {
+    // "Instantiate" the generic function without calling it.
+    let _ = mem::transmute::<CowRcStr<'_>, Option<CowRcStr<'_>>>;
+}
+
+impl<'a> From<Cow<'a, str>> for CowRcStr<'a> {
+    #[inline]
+    fn from(s: Cow<'a, str>) -> Self {
+        match s {
+            Cow::Borrowed(s) => CowRcStr::from(s),
+            Cow::Owned(s) => CowRcStr::from(s),
+        }
+    }
+}
+
+impl<'a> From<&'a str> for CowRcStr<'a> {
+    #[inline]
+    fn from(s: &'a str) -> Self {
+        let len = s.len();
+        assert!(len < usize::MAX);
+        CowRcStr {
+            ptr: unsafe { ptr::NonNull::new_unchecked(s.as_ptr() as *mut ()) },
+            borrowed_len_or_max: len,
+            phantom: marker::PhantomData,
+        }
+    }
+}
+
+impl<'a> From<String> for CowRcStr<'a> {
+    #[inline]
+    fn from(s: String) -> Self {
+        CowRcStr::from_rc(Rc::new(s))
+    }
+}
+
+impl<'a> CowRcStr<'a> {
+    #[inline]
+    fn from_rc(s: Rc<String>) -> Self {
+        let ptr = unsafe { ptr::NonNull::new_unchecked(Rc::into_raw(s) as *mut ()) };
+        CowRcStr {
+            ptr,
+            borrowed_len_or_max: usize::MAX,
+            phantom: marker::PhantomData,
+        }
+    }
+
+    #[inline]
+    fn unpack(&self) -> Result<&'a str, *const String> {
+        if self.borrowed_len_or_max == usize::MAX {
+            Err(self.ptr.as_ptr() as *const String)
+        } else {
+            unsafe {
+                Ok(str::from_utf8_unchecked(slice::from_raw_parts(
+                    self.ptr.as_ptr() as *const u8,
+                    self.borrowed_len_or_max,
+                )))
+            }
+        }
+    }
+}
+
+impl<'a> Clone for CowRcStr<'a> {
+    #[inline]
+    fn clone(&self) -> Self {
+        match self.unpack() {
+            Err(ptr) => {
+                let rc = unsafe { Rc::from_raw(ptr) };
+                let new_rc = rc.clone();
+                mem::forget(rc); // Don’t actually take ownership of this strong reference
+                CowRcStr::from_rc(new_rc)
+            }
+            Ok(_) => CowRcStr { ..*self },
+        }
+    }
+}
+
+impl<'a> Drop for CowRcStr<'a> {
+    #[inline]
+    fn drop(&mut self) {
+        if let Err(ptr) = self.unpack() {
+            mem::drop(unsafe { Rc::from_raw(ptr) })
+        }
+    }
+}
+
+impl<'a> ops::Deref for CowRcStr<'a> {
+    type Target = str;
+
+    #[inline]
+    fn deref(&self) -> &str {
+        self.unpack().unwrap_or_else(|ptr| unsafe { &**ptr })
+    }
+}
+
+// Boilerplate / trivial impls below.
+
+impl<'a> AsRef<str> for CowRcStr<'a> {
+    #[inline]
+    fn as_ref(&self) -> &str {
+        self
+    }
+}
+
+impl<'a> Borrow<str> for CowRcStr<'a> {
+    #[inline]
+    fn borrow(&self) -> &str {
+        self
+    }
+}
+
+impl<'a> Default for CowRcStr<'a> {
+    #[inline]
+    fn default() -> Self {
+        Self::from("")
+    }
+}
+
+impl<'a> hash::Hash for CowRcStr<'a> {
+    #[inline]
+    fn hash<H: hash::Hasher>(&self, hasher: &mut H) {
+        str::hash(self, hasher)
+    }
+}
+
+impl<'a, T: AsRef<str>> PartialEq<T> for CowRcStr<'a> {
+    #[inline]
+    fn eq(&self, other: &T) -> bool {
+        str::eq(self, other.as_ref())
+    }
+}
+
+impl<'a, T: AsRef<str>> PartialOrd<T> for CowRcStr<'a> {
+    #[inline]
+    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
+        str::partial_cmp(self, other.as_ref())
+    }
+}
+
+impl<'a> Eq for CowRcStr<'a> {}
+
+impl<'a> Ord for CowRcStr<'a> {
+    #[inline]
+    fn cmp(&self, other: &Self) -> cmp::Ordering {
+        str::cmp(self, other)
+    }
+}
+
+impl<'a> fmt::Display for CowRcStr<'a> {
+    #[inline]
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        str::fmt(self, formatter)
+    }
+}
+
+impl<'a> fmt::Debug for CowRcStr<'a> {
+    #[inline]
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        str::fmt(self, formatter)
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/from_bytes.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/from_bytes.rs
new file mode 100644
index 000000000000..78a56d3e14fc
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/from_bytes.rs
@@ -0,0 +1,64 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Abstraction for avoiding a dependency from cssparser to an encoding library
+pub trait EncodingSupport {
+    /// One character encoding
+    type Encoding;
+
+    /// https://encoding.spec.whatwg.org/#concept-encoding-get
+    fn from_label(ascii_label: &[u8]) -> Option<Self::Encoding>;
+
+    /// Return the UTF-8 encoding
+    fn utf8() -> Self::Encoding;
+
+    /// Whether the given encoding is UTF-16BE or UTF-16LE
+    fn is_utf16_be_or_le(encoding: &Self::Encoding) -> bool;
+}
+
+/// Determine the character encoding of a CSS stylesheet.
+///
+/// This is based on the presence of a BOM (Byte Order Mark), an `@charset` rule, and
+/// encoding meta-information.
+///
+/// * `css_bytes`: A byte string.
+/// * `protocol_encoding`: The encoding label, if any, defined by HTTP or equivalent protocol.
+///     (e.g. via the `charset` parameter of the `Content-Type` header.)
+/// * `environment_encoding`: An optional `Encoding` object for the [environment encoding]
+///     (https://drafts.csswg.org/css-syntax/#environment-encoding), if any.
+///
+/// Returns the encoding to use.
+pub fn stylesheet_encoding<E>(
+    css: &[u8],
+    protocol_encoding_label: Option<&[u8]>,
+    environment_encoding: Option<E::Encoding>,
+) -> E::Encoding
+where
+    E: EncodingSupport,
+{
+    // https://drafts.csswg.org/css-syntax/#the-input-byte-stream
+    if let Some(label) = protocol_encoding_label {
+        if let Some(protocol_encoding) = E::from_label(label) {
+            return protocol_encoding;
+        };
+    };
+
+    let prefix = b"@charset \"";
+    if css.starts_with(prefix) {
+        let rest = &css[prefix.len()..];
+        if let Some(label_length) = rest.iter().position(|&b| b == b'"') {
+            if rest[label_length..].starts_with(b"\";") {
+                let label = &rest[..label_length];
+                if let Some(charset_encoding) = E::from_label(label) {
+                    if E::is_utf16_be_or_le(&charset_encoding) {
+                        return E::utf8();
+                    } else {
+                        return charset_encoding;
+                    }
+                }
+            }
+        }
+    }
+    environment_encoding.unwrap_or_else(E::utf8)
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs
new file mode 100644
index 000000000000..dc44fb743c5b
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs
@@ -0,0 +1,108 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![crate_name = "cssparser"]
+#![crate_type = "rlib"]
+#![cfg_attr(feature = "bench", feature(test))]
+#![deny(missing_docs)]
+
+/*!
+
+Implementation of [CSS Syntax Module Level 3](https://drafts.csswg.org/css-syntax/) for Rust.
+
+# Input
+
+Everything is based on `Parser` objects, which borrow a `&str` input.
+If you have bytes (from a file, the network, or something)
+and want to support character encodings other than UTF-8,
+see the `stylesheet_encoding` function,
+which can be used together with rust-encoding or encoding-rs.
+
+# Conventions for parsing functions
+
+* Take (at least) a `input: &mut cssparser::Parser` parameter
+* Return `Result<_, ()>`
+* When returning `Ok(_)`,
+  the function must have consumed exactly the amount of input that represents the parsed value.
+* When returning `Err(())`, any amount of input may have been consumed.
+
+As a consequence, when calling another parsing function, either:
+
+* Any `Err(())` return value must be propagated.
+  This happens by definition for tail calls,
+  and can otherwise be done with the `?` operator.
+* Or the call must be wrapped in a `Parser::try` call.
+  `try` takes a closure that takes a `Parser` and returns a `Result`,
+  calls it once,
+  and returns itself that same result.
+  If the result is `Err`,
+  it restores the position inside the input to the one saved before calling the closure.
+
+Examples:
+
+```{rust,ignore}
+// 'none' | <image>
+fn parse_background_image(context: &ParserContext, input: &mut Parser)
+                                    -> Result<Option<Image>, ()> {
+    if input.try_parse(|input| input.expect_ident_matching("none")).is_ok() {
+        Ok(None)
+    } else {
+        Image::parse(context, input).map(Some)  // tail call
+    }
+}
+```
+
+```{rust,ignore}
+// [ <length> | <percentage> ] [ <length> | <percentage> ]?
+fn parse_border_spacing(_context: &ParserContext, input: &mut Parser)
+                          -> Result<(LengthOrPercentage, LengthOrPercentage), ()> {
+    let first = LengthOrPercentage::parse?;
+    let second = input.try_parse(LengthOrPercentage::parse).unwrap_or(first);
+    (first, second)
+}
+```
+
+*/
+
+#![recursion_limit = "200"] // For color::parse_color_keyword
+
+pub use crate::cow_rc_str::CowRcStr;
+pub use crate::from_bytes::{stylesheet_encoding, EncodingSupport};
+#[doc(hidden)]
+pub use crate::macros::{
+    _cssparser_internal_create_uninit_array, _cssparser_internal_to_lowercase,
+};
+pub use crate::nth::parse_nth;
+pub use crate::parser::{BasicParseError, BasicParseErrorKind, ParseError, ParseErrorKind};
+pub use crate::parser::{Delimiter, Delimiters, Parser, ParserInput, ParserState};
+pub use crate::rules_and_declarations::{parse_important, parse_one_declaration};
+pub use crate::rules_and_declarations::{parse_one_rule, StyleSheetParser};
+pub use crate::rules_and_declarations::{AtRuleParser, QualifiedRuleParser};
+pub use crate::rules_and_declarations::{DeclarationParser, RuleBodyItemParser, RuleBodyParser};
+pub use crate::serializer::{serialize_identifier, serialize_name, serialize_string};
+pub use crate::serializer::{CssStringWriter, ToCss, TokenSerializationType};
+pub use crate::tokenizer::{SourceLocation, SourcePosition, Token};
+pub use crate::unicode_range::UnicodeRange;
+pub use cssparser_macros::*;
+#[doc(hidden)]
+pub use phf as _cssparser_internal_phf;
+
+#[macro_use]
+mod macros;
+
+mod rules_and_declarations;
+mod tokenizer;
+
+pub mod color;
+mod cow_rc_str;
+mod from_bytes;
+mod nth;
+mod parser;
+mod serializer;
+mod unicode_range;
+
+#[cfg(test)]
+mod size_of_tests;
+#[cfg(test)]
+mod tests;
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/macros.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/macros.rs
new file mode 100644
index 000000000000..67d836588442
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/macros.rs
@@ -0,0 +1,204 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::mem::MaybeUninit;
+
+/// Expands to a `match` expression with string patterns,
+/// matching case-insensitively in the ASCII range.
+///
+/// The patterns must not contain ASCII upper case letters. (They must be already be lower-cased.)
+///
+/// # Example
+///
+/// ```rust
+/// # fn main() {}  // Make doctest not wrap everything in its own main
+/// # fn dummy(function_name: &String) { let _ =
+/// cssparser::match_ignore_ascii_case! { &function_name,
+///     "rgb" => parse_rgb(..),
+/// #   #[cfg(not(something))]
+///     "rgba" => parse_rgba(..),
+///     "hsl" => parse_hsl(..),
+///     "hsla" => parse_hsla(..),
+///     _ => Err(format!("unknown function: {}", function_name))
+/// }
+/// # ;}
+/// # use std::ops::RangeFull;
+/// # fn parse_rgb(_: RangeFull) -> Result<(), String> { Ok(()) }
+/// # fn parse_rgba(_: RangeFull) -> Result<(), String> { Ok(()) }
+/// # fn parse_hsl(_: RangeFull) -> Result<(), String> { Ok(()) }
+/// # fn parse_hsla(_: RangeFull) -> Result<(), String> { Ok(()) }
+/// ```
+#[macro_export]
+macro_rules! match_ignore_ascii_case {
+    ( $input:expr,
+        $(
+            $( #[$meta: meta] )*
+            $( $pattern: pat )|+ $( if $guard: expr )? => $then: expr
+        ),+
+        $(,)?
+    ) => {
+        {
+            // This dummy module works around the feature gate
+            // `error[E0658]: procedural macros cannot be expanded to statements`
+            // by forcing the macro to be in an item context
+            // rather than expression/statement context,
+            // even though the macro only expands to items.
+            mod cssparser_internal {
+                $crate::_cssparser_internal_max_len! {
+                    $( $( $pattern )+ )+
+                }
+            }
+            $crate::_cssparser_internal_to_lowercase!($input, cssparser_internal::MAX_LENGTH => lowercase);
+            // "A" is a short string that we know is different for every string pattern,
+            // since we’ve verified that none of them include ASCII upper case letters.
+            match lowercase.unwrap_or("A") {
+                $(
+                    $( #[$meta] )*
+                    $( $pattern )|+ $( if $guard )? => $then,
+                )+
+            }
+        }
+    };
+}
+
+/// Define a function `$name(&str) -> Option<&'static $ValueType>`
+///
+/// The function finds a match for the input string
+/// in a [`phf` map](https://github.com/sfackler/rust-phf)
+/// and returns a reference to the corresponding value.
+/// Matching is case-insensitive in the ASCII range.
+///
+/// ## Example:
+///
+/// ```rust
+/// # fn main() {}  // Make doctest not wrap everything in its own main
+///
+/// fn color_rgb(input: &str) -> Option<(u8, u8, u8)> {
+///     cssparser::ascii_case_insensitive_phf_map! {
+///         keywords -> (u8, u8, u8) = {
+///             "red" => (255, 0, 0),
+///             "green" => (0, 255, 0),
+///             "blue" => (0, 0, 255),
+///         }
+///     }
+///     keywords::get(input).cloned()
+/// }
+/// ```
+///
+/// You can also iterate over the map entries by using `keywords::entries()`.
+#[macro_export]
+macro_rules! ascii_case_insensitive_phf_map {
+    ($name: ident -> $ValueType: ty = { $( $key: tt => $value: expr ),+ }) => {
+        ascii_case_insensitive_phf_map!($name -> $ValueType = { $( $key => $value, )+ })
+    };
+    ($name: ident -> $ValueType: ty = { $( $key: tt => $value: expr, )+ }) => {
+        use $crate::_cssparser_internal_phf as phf;
+
+        // See macro above for context.
+        mod cssparser_internal {
+            $crate::_cssparser_internal_max_len! {
+                $( $key )+
+            }
+        }
+
+        static MAP: phf::Map<&'static str, $ValueType> = phf::phf_map! {
+            $(
+                $key => $value,
+            )*
+        };
+
+        // While the obvious choice for this would be an inner module, it's not possible to
+        // reference from types from there, see:
+        // <https://github.com/rust-lang/rust/issues/114369>
+        //
+        // So we abuse a struct with static associated functions instead.
+        #[allow(non_camel_case_types)]
+        struct $name;
+        impl $name {
+            #[allow(dead_code)]
+            fn entries() -> impl Iterator<Item = (&'static &'static str, &'static $ValueType)> {
+                MAP.entries()
+            }
+
+            fn get(input: &str) -> Option<&'static $ValueType> {
+                $crate::_cssparser_internal_to_lowercase!(input, cssparser_internal::MAX_LENGTH => lowercase);
+                MAP.get(lowercase?)
+            }
+        }
+    }
+}
+
+/// Create a new array of MaybeUninit<T> items, in an uninitialized state.
+#[inline(always)]
+pub fn _cssparser_internal_create_uninit_array<const N: usize>() -> [MaybeUninit<u8>; N] {
+    unsafe {
+        // SAFETY: An uninitialized `[MaybeUninit<_>; LEN]` is valid.
+        // See: https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.uninit_array
+        MaybeUninit::<[MaybeUninit<u8>; N]>::uninit().assume_init()
+    }
+}
+
+/// Implementation detail of match_ignore_ascii_case! and ascii_case_insensitive_phf_map! macros.
+///
+/// **This macro is not part of the public API. It can change or be removed between any versions.**
+///
+/// Define a local variable named `$output`
+/// and assign it the result of calling `_cssparser_internal_to_lowercase`
+/// with a stack-allocated buffer of length `$BUFFER_SIZE`.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! _cssparser_internal_to_lowercase {
+    ($input: expr, $BUFFER_SIZE: expr => $output: ident) => {
+        let mut buffer = $crate::_cssparser_internal_create_uninit_array::<{ $BUFFER_SIZE }>();
+        let input: &str = $input;
+        let $output = $crate::_cssparser_internal_to_lowercase(&mut buffer, input);
+    };
+}
+
+/// Implementation detail of match_ignore_ascii_case! and ascii_case_insensitive_phf_map! macros.
+///
+/// **This function is not part of the public API. It can change or be removed between any versions.**
+///
+/// If `input` is larger than buffer, return `None`.
+/// Otherwise, return `input` ASCII-lowercased, using `buffer` as temporary space if necessary.
+#[doc(hidden)]
+#[allow(non_snake_case)]
+#[inline]
+pub fn _cssparser_internal_to_lowercase<'a>(
+    buffer: &'a mut [MaybeUninit<u8>],
+    input: &'a str,
+) -> Option<&'a str> {
+    let buffer = buffer.get_mut(..input.len())?;
+
+    #[cold]
+    fn make_ascii_lowercase<'a>(
+        buffer: &'a mut [MaybeUninit<u8>],
+        input: &'a str,
+        first_uppercase: usize,
+    ) -> &'a str {
+        // This cast doesn't change the pointer's validity
+        // since `u8` has the same layout as `MaybeUninit<u8>`:
+        let input_bytes =
+            unsafe { &*(input.as_bytes() as *const [u8] as *const [MaybeUninit<u8>]) };
+
+        buffer.copy_from_slice(input_bytes);
+
+        // Same as above re layout, plus these bytes have been initialized:
+        let buffer = unsafe { &mut *(buffer as *mut [MaybeUninit<u8>] as *mut [u8]) };
+
+        buffer[first_uppercase..].make_ascii_lowercase();
+        // `buffer` was initialized to a copy of `input`
+        // (which is `&str` so well-formed UTF-8)
+        // then ASCII-lowercased (which preserves UTF-8 well-formedness):
+        unsafe { ::std::str::from_utf8_unchecked(buffer) }
+    }
+
+    Some(
+        match input.bytes().position(|byte| byte.is_ascii_uppercase()) {
+            Some(first_uppercase) => make_ascii_lowercase(buffer, input, first_uppercase),
+            // common case: input is already lower-case
+            None => input,
+        },
+    )
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/nth.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/nth.rs
new file mode 100644
index 000000000000..4fe5a6bc044a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/nth.rs
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use super::{BasicParseError, Parser, ParserInput, Token};
+
+/// Parse the *An+B* notation, as found in the `:nth-child()` selector.
+/// The input is typically the arguments of a function,
+/// in which case the caller needs to check if the arguments’ parser is exhausted.
+/// Return `Ok((A, B))`, or an `Err(..)` for a syntax error.
+pub fn parse_nth<'i>(input: &mut Parser<'i, '_>) -> Result<(i32, i32), BasicParseError<'i>> {
+    match *input.next()? {
+        Token::Number {
+            int_value: Some(b), ..
+        } => Ok((0, b)),
+        Token::Dimension {
+            int_value: Some(a),
+            ref unit,
+            ..
+        } => {
+            match_ignore_ascii_case! {
+                unit,
+                "n" => Ok(parse_b(input, a)?),
+                "n-" => Ok(parse_signless_b(input, a, -1)?),
+                _ => match parse_n_dash_digits(unit) {
+                    Ok(b) => Ok((a, b)),
+                    Err(()) => {
+                        let unit = unit.clone();
+                        Err(input.new_basic_unexpected_token_error(Token::Ident(unit)))
+                    }
+                }
+            }
+        }
+        Token::Ident(ref value) => {
+            match_ignore_ascii_case! { value,
+                "even" => Ok((2, 0)),
+                "odd" => Ok((2, 1)),
+                "n" => Ok(parse_b(input, 1)?),
+                "-n" => Ok(parse_b(input, -1)?),
+                "n-" => Ok(parse_signless_b(input, 1, -1)?),
+                "-n-" => Ok(parse_signless_b(input, -1, -1)?),
+                _ => {
+                    let (slice, a) = if let Some(stripped) = value.strip_prefix('-') {
+                        (stripped, -1)
+                    } else {
+                        (&**value, 1)
+                    };
+                    match parse_n_dash_digits(slice) {
+                        Ok(b) => Ok((a, b)),
+                        Err(()) => {
+                            let value = value.clone();
+                            Err(input.new_basic_unexpected_token_error(Token::Ident(value)))
+                        }
+                    }
+                }
+            }
+        }
+        Token::Delim('+') => match *input.next_including_whitespace()? {
+            Token::Ident(ref value) => {
+                match_ignore_ascii_case! { value,
+                    "n" => parse_b(input, 1),
+                    "n-" => parse_signless_b(input, 1, -1),
+                    _ => match parse_n_dash_digits(value) {
+                        Ok(b) => Ok((1, b)),
+                        Err(()) => {
+                            let value = value.clone();
+                            Err(input.new_basic_unexpected_token_error(Token::Ident(value)))
+                        }
+                    }
+                }
+            }
+            ref token => {
+                let token = token.clone();
+                Err(input.new_basic_unexpected_token_error(token))
+            }
+        },
+        ref token => {
+            let token = token.clone();
+            Err(input.new_basic_unexpected_token_error(token))
+        }
+    }
+}
+
+fn parse_b<'i>(input: &mut Parser<'i, '_>, a: i32) -> Result<(i32, i32), BasicParseError<'i>> {
+    let start = input.state();
+    match input.next() {
+        Ok(&Token::Delim('+')) => parse_signless_b(input, a, 1),
+        Ok(&Token::Delim('-')) => parse_signless_b(input, a, -1),
+        Ok(&Token::Number {
+            has_sign: true,
+            int_value: Some(b),
+            ..
+        }) => Ok((a, b)),
+        _ => {
+            input.reset(&start);
+            Ok((a, 0))
+        }
+    }
+}
+
+fn parse_signless_b<'i>(
+    input: &mut Parser<'i, '_>,
+    a: i32,
+    b_sign: i32,
+) -> Result<(i32, i32), BasicParseError<'i>> {
+    // FIXME: remove .clone() when lifetimes are non-lexical.
+    match input.next()?.clone() {
+        Token::Number {
+            has_sign: false,
+            int_value: Some(b),
+            ..
+        } => Ok((a, b_sign * b)),
+        token => Err(input.new_basic_unexpected_token_error(token)),
+    }
+}
+
+fn parse_n_dash_digits(string: &str) -> Result<i32, ()> {
+    let bytes = string.as_bytes();
+    if bytes.len() >= 3
+        && bytes[..2].eq_ignore_ascii_case(b"n-")
+        && bytes[2..].iter().all(|&c| c.is_ascii_digit())
+    {
+        Ok(parse_number_saturate(&string[1..]).unwrap()) // Include the minus sign
+    } else {
+        Err(())
+    }
+}
+
+fn parse_number_saturate(string: &str) -> Result<i32, ()> {
+    let mut input = ParserInput::new(string);
+    let mut parser = Parser::new(&mut input);
+    let int = if let Ok(&Token::Number {
+        int_value: Some(int),
+        ..
+    }) = parser.next_including_whitespace_and_comments()
+    {
+        int
+    } else {
+        return Err(());
+    };
+    if !parser.is_exhausted() {
+        return Err(());
+    }
+    Ok(int)
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/parser.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/parser.rs
new file mode 100644
index 000000000000..dd35fc50ed42
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/parser.rs
@@ -0,0 +1,1175 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::cow_rc_str::CowRcStr;
+use crate::tokenizer::{SourceLocation, SourcePosition, Token, Tokenizer};
+use smallvec::SmallVec;
+use std::fmt;
+use std::ops::BitOr;
+use std::ops::Range;
+
+/// A capture of the internal state of a `Parser` (including the position within the input),
+/// obtained from the `Parser::position` method.
+///
+/// Can be used with the `Parser::reset` method to restore that state.
+/// Should only be used with the `Parser` instance it came from.
+#[derive(Debug, Clone)]
+pub struct ParserState {
+    pub(crate) position: usize,
+    pub(crate) current_line_start_position: usize,
+    pub(crate) current_line_number: u32,
+    pub(crate) at_start_of: Option<BlockType>,
+}
+
+impl ParserState {
+    /// The position from the start of the input, counted in UTF-8 bytes.
+    #[inline]
+    pub fn position(&self) -> SourcePosition {
+        SourcePosition(self.position)
+    }
+
+    /// The line number and column number
+    #[inline]
+    pub fn source_location(&self) -> SourceLocation {
+        SourceLocation {
+            line: self.current_line_number,
+            column: (self.position - self.current_line_start_position + 1) as u32,
+        }
+    }
+}
+
+/// When parsing until a given token, sometimes the caller knows that parsing is going to restart
+/// at some earlier point, and consuming until we find a top level delimiter is just wasted work.
+///
+/// In that case, callers can pass ParseUntilErrorBehavior::Stop to avoid doing all that wasted
+/// work.
+///
+/// This is important for things like CSS nesting, where something like:
+///
+///   foo:is(..) {
+///     ...
+///   }
+///
+/// Would need to scan the whole {} block to find a semicolon, only for parsing getting restarted
+/// as a qualified rule later.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ParseUntilErrorBehavior {
+    /// Consume until we see the relevant delimiter or the end of the stream.
+    Consume,
+    /// Eagerly error.
+    Stop,
+}
+
+/// Details about a `BasicParseError`
+#[derive(Clone, Debug, PartialEq)]
+pub enum BasicParseErrorKind<'i> {
+    /// An unexpected token was encountered.
+    UnexpectedToken(Token<'i>),
+    /// The end of the input was encountered unexpectedly.
+    EndOfInput,
+    /// An `@` rule was encountered that was invalid.
+    AtRuleInvalid(CowRcStr<'i>),
+    /// The body of an '@' rule was invalid.
+    AtRuleBodyInvalid,
+    /// A qualified rule was encountered that was invalid.
+    QualifiedRuleInvalid,
+}
+
+impl<'i> fmt::Display for BasicParseErrorKind<'i> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            BasicParseErrorKind::UnexpectedToken(token) => {
+                write!(f, "unexpected token: {:?}", token)
+            }
+            BasicParseErrorKind::EndOfInput => write!(f, "unexpected end of input"),
+            BasicParseErrorKind::AtRuleInvalid(rule) => {
+                write!(f, "invalid @ rule encountered: '@{}'", rule)
+            }
+            BasicParseErrorKind::AtRuleBodyInvalid => write!(f, "invalid @ rule body encountered"),
+            BasicParseErrorKind::QualifiedRuleInvalid => {
+                write!(f, "invalid qualified rule encountered")
+            }
+        }
+    }
+}
+
+/// The fundamental parsing errors that can be triggered by built-in parsing routines.
+#[derive(Clone, Debug, PartialEq)]
+pub struct BasicParseError<'i> {
+    /// Details of this error
+    pub kind: BasicParseErrorKind<'i>,
+    /// Location where this error occurred
+    pub location: SourceLocation,
+}
+
+impl<'i, T> From<BasicParseError<'i>> for ParseError<'i, T> {
+    #[inline]
+    fn from(this: BasicParseError<'i>) -> ParseError<'i, T> {
+        ParseError {
+            kind: ParseErrorKind::Basic(this.kind),
+            location: this.location,
+        }
+    }
+}
+
+impl SourceLocation {
+    /// Create a new BasicParseError at this location for an unexpected token
+    #[inline]
+    pub fn new_basic_unexpected_token_error(self, token: Token<'_>) -> BasicParseError<'_> {
+        self.new_basic_error(BasicParseErrorKind::UnexpectedToken(token))
+    }
+
+    /// Create a new BasicParseError at this location
+    #[inline]
+    pub fn new_basic_error(self, kind: BasicParseErrorKind<'_>) -> BasicParseError<'_> {
+        BasicParseError {
+            kind,
+            location: self,
+        }
+    }
+
+    /// Create a new ParseError at this location for an unexpected token
+    #[inline]
+    pub fn new_unexpected_token_error<E>(self, token: Token<'_>) -> ParseError<'_, E> {
+        self.new_error(BasicParseErrorKind::UnexpectedToken(token))
+    }
+
+    /// Create a new basic ParseError at the current location
+    #[inline]
+    pub fn new_error<E>(self, kind: BasicParseErrorKind<'_>) -> ParseError<'_, E> {
+        ParseError {
+            kind: ParseErrorKind::Basic(kind),
+            location: self,
+        }
+    }
+
+    /// Create a new custom ParseError at this location
+    #[inline]
+    pub fn new_custom_error<'i, E1: Into<E2>, E2>(self, error: E1) -> ParseError<'i, E2> {
+        ParseError {
+            kind: ParseErrorKind::Custom(error.into()),
+            location: self,
+        }
+    }
+}
+
+/// Details of a `ParseError`
+#[derive(Clone, Debug, PartialEq)]
+pub enum ParseErrorKind<'i, T: 'i> {
+    /// A fundamental parse error from a built-in parsing routine.
+    Basic(BasicParseErrorKind<'i>),
+    /// A parse error reported by downstream consumer code.
+    Custom(T),
+}
+
+impl<'i, T> ParseErrorKind<'i, T> {
+    /// Like `std::convert::Into::into`
+    pub fn into<U>(self) -> ParseErrorKind<'i, U>
+    where
+        T: Into<U>,
+    {
+        match self {
+            ParseErrorKind::Basic(basic) => ParseErrorKind::Basic(basic),
+            ParseErrorKind::Custom(custom) => ParseErrorKind::Custom(custom.into()),
+        }
+    }
+}
+
+impl<'i, E: fmt::Display> fmt::Display for ParseErrorKind<'i, E> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            ParseErrorKind::Basic(ref basic) => basic.fmt(f),
+            ParseErrorKind::Custom(ref custom) => custom.fmt(f),
+        }
+    }
+}
+
+/// Extensible parse errors that can be encountered by client parsing implementations.
+#[derive(Clone, Debug, PartialEq)]
+pub struct ParseError<'i, E> {
+    /// Details of this error
+    pub kind: ParseErrorKind<'i, E>,
+    /// Location where this error occurred
+    pub location: SourceLocation,
+}
+
+impl<'i, T> ParseError<'i, T> {
+    /// Extract the fundamental parse error from an extensible error.
+    pub fn basic(self) -> BasicParseError<'i> {
+        match self.kind {
+            ParseErrorKind::Basic(kind) => BasicParseError {
+                kind,
+                location: self.location,
+            },
+            ParseErrorKind::Custom(_) => panic!("Not a basic parse error"),
+        }
+    }
+
+    /// Like `std::convert::Into::into`
+    pub fn into<U>(self) -> ParseError<'i, U>
+    where
+        T: Into<U>,
+    {
+        ParseError {
+            kind: self.kind.into(),
+            location: self.location,
+        }
+    }
+}
+
+impl<'i, E: fmt::Display> fmt::Display for ParseError<'i, E> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.kind.fmt(f)
+    }
+}
+
+impl<'i, E: fmt::Display + fmt::Debug> std::error::Error for ParseError<'i, E> {}
+
+/// The owned input for a parser.
+pub struct ParserInput<'i> {
+    tokenizer: Tokenizer<'i>,
+    cached_token: Option<CachedToken<'i>>,
+}
+
+struct CachedToken<'i> {
+    token: Token<'i>,
+    start_position: SourcePosition,
+    end_state: ParserState,
+}
+
+impl<'i> ParserInput<'i> {
+    /// Create a new input for a parser.
+    pub fn new(input: &'i str) -> ParserInput<'i> {
+        ParserInput {
+            tokenizer: Tokenizer::new(input),
+            cached_token: None,
+        }
+    }
+
+    #[inline]
+    fn cached_token_ref(&self) -> &Token<'i> {
+        &self.cached_token.as_ref().unwrap().token
+    }
+}
+
+/// A CSS parser that borrows its `&str` input,
+/// yields `Token`s,
+/// and keeps track of nested blocks and functions.
+pub struct Parser<'i, 't> {
+    input: &'t mut ParserInput<'i>,
+    /// If `Some(_)`, .parse_nested_block() can be called.
+    at_start_of: Option<BlockType>,
+    /// For parsers from `parse_until` or `parse_nested_block`
+    stop_before: Delimiters,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub(crate) enum BlockType {
+    Parenthesis,
+    SquareBracket,
+    CurlyBracket,
+}
+
+impl BlockType {
+    fn opening(token: &Token) -> Option<BlockType> {
+        match *token {
+            Token::Function(_) | Token::ParenthesisBlock => Some(BlockType::Parenthesis),
+            Token::SquareBracketBlock => Some(BlockType::SquareBracket),
+            Token::CurlyBracketBlock => Some(BlockType::CurlyBracket),
+            _ => None,
+        }
+    }
+
+    fn closing(token: &Token) -> Option<BlockType> {
+        match *token {
+            Token::CloseParenthesis => Some(BlockType::Parenthesis),
+            Token::CloseSquareBracket => Some(BlockType::SquareBracket),
+            Token::CloseCurlyBracket => Some(BlockType::CurlyBracket),
+            _ => None,
+        }
+    }
+}
+
+/// A set of characters, to be used with the `Parser::parse_until*` methods.
+///
+/// The union of two sets can be obtained with the `|` operator. Example:
+///
+/// ```{rust,ignore}
+/// input.parse_until_before(Delimiter::CurlyBracketBlock | Delimiter::Semicolon)
+/// ```
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct Delimiters {
+    bits: u8,
+}
+
+/// `Delimiters` constants.
+#[allow(non_upper_case_globals, non_snake_case)]
+pub mod Delimiter {
+    use super::Delimiters;
+
+    /// The empty delimiter set
+    pub const None: Delimiters = Delimiters { bits: 0 };
+    /// The delimiter set with only the `{` opening curly bracket
+    pub const CurlyBracketBlock: Delimiters = Delimiters { bits: 1 << 1 };
+    /// The delimiter set with only the `;` semicolon
+    pub const Semicolon: Delimiters = Delimiters { bits: 1 << 2 };
+    /// The delimiter set with only the `!` exclamation point
+    pub const Bang: Delimiters = Delimiters { bits: 1 << 3 };
+    /// The delimiter set with only the `,` comma
+    pub const Comma: Delimiters = Delimiters { bits: 1 << 4 };
+}
+
+#[allow(non_upper_case_globals, non_snake_case)]
+mod ClosingDelimiter {
+    use super::Delimiters;
+
+    pub const CloseCurlyBracket: Delimiters = Delimiters { bits: 1 << 5 };
+    pub const CloseSquareBracket: Delimiters = Delimiters { bits: 1 << 6 };
+    pub const CloseParenthesis: Delimiters = Delimiters { bits: 1 << 7 };
+}
+
+impl BitOr<Delimiters> for Delimiters {
+    type Output = Delimiters;
+
+    #[inline]
+    fn bitor(self, other: Delimiters) -> Delimiters {
+        Delimiters {
+            bits: self.bits | other.bits,
+        }
+    }
+}
+
+impl Delimiters {
+    #[inline]
+    fn contains(self, other: Delimiters) -> bool {
+        (self.bits & other.bits) != 0
+    }
+
+    #[inline]
+    pub(crate) fn from_byte(byte: Option<u8>) -> Delimiters {
+        const TABLE: [Delimiters; 256] = {
+            let mut table = [Delimiter::None; 256];
+            table[b';' as usize] = Delimiter::Semicolon;
+            table[b'!' as usize] = Delimiter::Bang;
+            table[b',' as usize] = Delimiter::Comma;
+            table[b'{' as usize] = Delimiter::CurlyBracketBlock;
+            table[b'}' as usize] = ClosingDelimiter::CloseCurlyBracket;
+            table[b']' as usize] = ClosingDelimiter::CloseSquareBracket;
+            table[b')' as usize] = ClosingDelimiter::CloseParenthesis;
+            table
+        };
+
+        match byte {
+            None => Delimiter::None,
+            Some(b) => TABLE[b as usize],
+        }
+    }
+}
+
+/// Used in some `fn expect_*` methods
+macro_rules! expect {
+    ($parser: ident, $($branches: tt)+) => {
+        {
+            let start_location = $parser.current_source_location();
+            match *$parser.next()? {
+                $($branches)+
+                ref token => {
+                    return Err(start_location.new_basic_unexpected_token_error(token.clone()))
+                }
+            }
+        }
+    }
+}
+
+impl<'i: 't, 't> Parser<'i, 't> {
+    /// Create a new parser
+    #[inline]
+    pub fn new(input: &'t mut ParserInput<'i>) -> Parser<'i, 't> {
+        Parser {
+            input,
+            at_start_of: None,
+            stop_before: Delimiter::None,
+        }
+    }
+
+    /// Return the current line that is being parsed.
+    pub fn current_line(&self) -> &'i str {
+        self.input.tokenizer.current_source_line()
+    }
+
+    /// Check whether the input is exhausted. That is, if `.next()` would return a token.
+    ///
+    /// This ignores whitespace and comments.
+    #[inline]
+    pub fn is_exhausted(&mut self) -> bool {
+        self.expect_exhausted().is_ok()
+    }
+
+    /// Check whether the input is exhausted. That is, if `.next()` would return a token.
+    /// Return a `Result` so that the `?` operator can be used: `input.expect_exhausted()?`
+    ///
+    /// This ignores whitespace and comments.
+    #[inline]
+    pub fn expect_exhausted(&mut self) -> Result<(), BasicParseError<'i>> {
+        let start = self.state();
+        let result = match self.next() {
+            Err(BasicParseError {
+                kind: BasicParseErrorKind::EndOfInput,
+                ..
+            }) => Ok(()),
+            Err(e) => unreachable!("Unexpected error encountered: {:?}", e),
+            Ok(t) => Err(start
+                .source_location()
+                .new_basic_unexpected_token_error(t.clone())),
+        };
+        self.reset(&start);
+        result
+    }
+
+    /// Return the current position within the input.
+    ///
+    /// This can be used with the `Parser::slice` and `slice_from` methods.
+    #[inline]
+    pub fn position(&self) -> SourcePosition {
+        self.input.tokenizer.position()
+    }
+
+    /// The current line number and column number.
+    #[inline]
+    pub fn current_source_location(&self) -> SourceLocation {
+        self.input.tokenizer.current_source_location()
+    }
+
+    /// The source map URL, if known.
+    ///
+    /// The source map URL is extracted from a specially formatted
+    /// comment.  The last such comment is used, so this value may
+    /// change as parsing proceeds.
+    pub fn current_source_map_url(&self) -> Option<&str> {
+        self.input.tokenizer.current_source_map_url()
+    }
+
+    /// The source URL, if known.
+    ///
+    /// The source URL is extracted from a specially formatted
+    /// comment.  The last such comment is used, so this value may
+    /// change as parsing proceeds.
+    pub fn current_source_url(&self) -> Option<&str> {
+        self.input.tokenizer.current_source_url()
+    }
+
+    /// Create a new BasicParseError at the current location
+    #[inline]
+    pub fn new_basic_error(&self, kind: BasicParseErrorKind<'i>) -> BasicParseError<'i> {
+        self.current_source_location().new_basic_error(kind)
+    }
+
+    /// Create a new basic ParseError at the current location
+    #[inline]
+    pub fn new_error<E>(&self, kind: BasicParseErrorKind<'i>) -> ParseError<'i, E> {
+        self.current_source_location().new_error(kind)
+    }
+
+    /// Create a new custom BasicParseError at the current location
+    #[inline]
+    pub fn new_custom_error<E1: Into<E2>, E2>(&self, error: E1) -> ParseError<'i, E2> {
+        self.current_source_location().new_custom_error(error)
+    }
+
+    /// Create a new unexpected token BasicParseError at the current location
+    #[inline]
+    pub fn new_basic_unexpected_token_error(&self, token: Token<'i>) -> BasicParseError<'i> {
+        self.new_basic_error(BasicParseErrorKind::UnexpectedToken(token))
+    }
+
+    /// Create a new unexpected token ParseError at the current location
+    #[inline]
+    pub fn new_unexpected_token_error<E>(&self, token: Token<'i>) -> ParseError<'i, E> {
+        self.new_error(BasicParseErrorKind::UnexpectedToken(token))
+    }
+
+    /// Create a new unexpected token or EOF ParseError at the current location
+    #[inline]
+    pub fn new_error_for_next_token<E>(&mut self) -> ParseError<'i, E> {
+        let token = match self.next() {
+            Ok(token) => token.clone(),
+            Err(e) => return e.into(),
+        };
+        self.new_error(BasicParseErrorKind::UnexpectedToken(token))
+    }
+
+    /// Return the current internal state of the parser (including position within the input).
+    ///
+    /// This state can later be restored with the `Parser::reset` method.
+    #[inline]
+    pub fn state(&self) -> ParserState {
+        ParserState {
+            at_start_of: self.at_start_of,
+            ..self.input.tokenizer.state()
+        }
+    }
+
+    /// Advance the input until the next token that’s not whitespace or a comment.
+    #[inline]
+    pub fn skip_whitespace(&mut self) {
+        if let Some(block_type) = self.at_start_of.take() {
+            consume_until_end_of_block(block_type, &mut self.input.tokenizer);
+        }
+
+        self.input.tokenizer.skip_whitespace()
+    }
+
+    #[inline]
+    pub(crate) fn skip_cdc_and_cdo(&mut self) {
+        if let Some(block_type) = self.at_start_of.take() {
+            consume_until_end_of_block(block_type, &mut self.input.tokenizer);
+        }
+
+        self.input.tokenizer.skip_cdc_and_cdo()
+    }
+
+    #[inline]
+    pub(crate) fn next_byte(&self) -> Option<u8> {
+        let byte = self.input.tokenizer.next_byte();
+        if self.stop_before.contains(Delimiters::from_byte(byte)) {
+            return None;
+        }
+        byte
+    }
+
+    /// Restore the internal state of the parser (including position within the input)
+    /// to what was previously saved by the `Parser::position` method.
+    ///
+    /// Should only be used with `SourcePosition` values from the same `Parser` instance.
+    #[inline]
+    pub fn reset(&mut self, state: &ParserState) {
+        self.input.tokenizer.reset(state);
+        self.at_start_of = state.at_start_of;
+    }
+
+    /// Start looking for `var()` / `env()` functions. (See the
+    /// `.seen_var_or_env_functions()` method.)
+    #[inline]
+    pub fn look_for_var_or_env_functions(&mut self) {
+        self.input.tokenizer.look_for_var_or_env_functions()
+    }
+
+    /// Return whether a `var()` or `env()` function has been seen by the
+    /// tokenizer since either `look_for_var_or_env_functions` was called, and
+    /// stop looking.
+    #[inline]
+    pub fn seen_var_or_env_functions(&mut self) -> bool {
+        self.input.tokenizer.seen_var_or_env_functions()
+    }
+
+    /// The old name of `try_parse`, which requires raw identifiers in the Rust 2018 edition.
+    #[inline]
+    pub fn r#try<F, T, E>(&mut self, thing: F) -> Result<T, E>
+    where
+        F: FnOnce(&mut Parser<'i, 't>) -> Result<T, E>,
+    {
+        self.try_parse(thing)
+    }
+
+    /// Execute the given closure, passing it the parser.
+    /// If the result (returned unchanged) is `Err`,
+    /// the internal state of the parser  (including position within the input)
+    /// is restored to what it was before the call.
+    #[inline]
+    pub fn try_parse<F, T, E>(&mut self, thing: F) -> Result<T, E>
+    where
+        F: FnOnce(&mut Parser<'i, 't>) -> Result<T, E>,
+    {
+        let start = self.state();
+        let result = thing(self);
+        if result.is_err() {
+            self.reset(&start)
+        }
+        result
+    }
+
+    /// Return a slice of the CSS input
+    #[inline]
+    pub fn slice(&self, range: Range<SourcePosition>) -> &'i str {
+        self.input.tokenizer.slice(range)
+    }
+
+    /// Return a slice of the CSS input, from the given position to the current one.
+    #[inline]
+    pub fn slice_from(&self, start_position: SourcePosition) -> &'i str {
+        self.input.tokenizer.slice_from(start_position)
+    }
+
+    /// Return the next token in the input that is neither whitespace or a comment,
+    /// and advance the position accordingly.
+    ///
+    /// After returning a `Function`, `ParenthesisBlock`,
+    /// `CurlyBracketBlock`, or `SquareBracketBlock` token,
+    /// the next call will skip until after the matching `CloseParenthesis`,
+    /// `CloseCurlyBracket`, or `CloseSquareBracket` token.
+    ///
+    /// See the `Parser::parse_nested_block` method to parse the content of functions or blocks.
+    ///
+    /// This only returns a closing token when it is unmatched (and therefore an error).
+    #[allow(clippy::should_implement_trait)]
+    pub fn next(&mut self) -> Result<&Token<'i>, BasicParseError<'i>> {
+        self.skip_whitespace();
+        self.next_including_whitespace_and_comments()
+    }
+
+    /// Same as `Parser::next`, but does not skip whitespace tokens.
+    pub fn next_including_whitespace(&mut self) -> Result<&Token<'i>, BasicParseError<'i>> {
+        loop {
+            match self.next_including_whitespace_and_comments() {
+                Err(e) => return Err(e),
+                Ok(&Token::Comment(_)) => {}
+                _ => break,
+            }
+        }
+        Ok(self.input.cached_token_ref())
+    }
+
+    /// Same as `Parser::next`, but does not skip whitespace or comment tokens.
+    ///
+    /// **Note**: This should only be used in contexts like a CSS pre-processor
+    /// where comments are preserved.
+    /// When parsing higher-level values, per the CSS Syntax specification,
+    /// comments should always be ignored between tokens.
+    pub fn next_including_whitespace_and_comments(
+        &mut self,
+    ) -> Result<&Token<'i>, BasicParseError<'i>> {
+        if let Some(block_type) = self.at_start_of.take() {
+            consume_until_end_of_block(block_type, &mut self.input.tokenizer);
+        }
+
+        let byte = self.input.tokenizer.next_byte();
+        if self.stop_before.contains(Delimiters::from_byte(byte)) {
+            return Err(self.new_basic_error(BasicParseErrorKind::EndOfInput));
+        }
+
+        let token_start_position = self.input.tokenizer.position();
+        let using_cached_token = self
+            .input
+            .cached_token
+            .as_ref()
+            .map_or(false, |cached_token| {
+                cached_token.start_position == token_start_position
+            });
+        let token = if using_cached_token {
+            let cached_token = self.input.cached_token.as_ref().unwrap();
+            self.input.tokenizer.reset(&cached_token.end_state);
+            if let Token::Function(ref name) = cached_token.token {
+                self.input.tokenizer.see_function(name)
+            }
+            &cached_token.token
+        } else {
+            let new_token = self
+                .input
+                .tokenizer
+                .next()
+                .map_err(|()| self.new_basic_error(BasicParseErrorKind::EndOfInput))?;
+            self.input.cached_token = Some(CachedToken {
+                token: new_token,
+                start_position: token_start_position,
+                end_state: self.input.tokenizer.state(),
+            });
+            self.input.cached_token_ref()
+        };
+
+        if let Some(block_type) = BlockType::opening(token) {
+            self.at_start_of = Some(block_type);
+        }
+        Ok(token)
+    }
+
+    /// Have the given closure parse something, then check the the input is exhausted.
+    /// The result is overridden to an `Err(..)` if some input remains.
+    ///
+    /// This can help tell e.g. `color: green;` from `color: green 4px;`
+    #[inline]
+    pub fn parse_entirely<F, T, E>(&mut self, parse: F) -> Result<T, ParseError<'i, E>>
+    where
+        F: FnOnce(&mut Parser<'i, 't>) -> Result<T, ParseError<'i, E>>,
+    {
+        let result = parse(self)?;
+        self.expect_exhausted()?;
+        Ok(result)
+    }
+
+    /// Parse a list of comma-separated values, all with the same syntax.
+    ///
+    /// The given closure is called repeatedly with a "delimited" parser
+    /// (see the `Parser::parse_until_before` method) so that it can over
+    /// consume the input past a comma at this block/function nesting level.
+    ///
+    /// Successful results are accumulated in a vector.
+    ///
+    /// This method returns an`Err(..)` the first time that a closure call does,
+    /// or if a closure call leaves some input before the next comma or the end
+    /// of the input.
+    #[inline]
+    pub fn parse_comma_separated<F, T, E>(
+        &mut self,
+        parse_one: F,
+    ) -> Result<Vec<T>, ParseError<'i, E>>
+    where
+        F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        self.parse_comma_separated_internal(parse_one, /* ignore_errors = */ false)
+    }
+
+    /// Like `parse_comma_separated`, but ignores errors on unknown components,
+    /// rather than erroring out in the whole list.
+    ///
+    /// Caller must deal with the fact that the resulting list might be empty,
+    /// if there's no valid component on the list.
+    #[inline]
+    pub fn parse_comma_separated_ignoring_errors<F, T, E: 'i>(&mut self, parse_one: F) -> Vec<T>
+    where
+        F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        match self.parse_comma_separated_internal(parse_one, /* ignore_errors = */ true) {
+            Ok(values) => values,
+            Err(..) => unreachable!(),
+        }
+    }
+
+    #[inline]
+    fn parse_comma_separated_internal<F, T, E>(
+        &mut self,
+        mut parse_one: F,
+        ignore_errors: bool,
+    ) -> Result<Vec<T>, ParseError<'i, E>>
+    where
+        F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        // Vec grows from 0 to 4 by default on first push().  So allocate with
+        // capacity 1, so in the somewhat common case of only one item we don't
+        // way overallocate.  Note that we always push at least one item if
+        // parsing succeeds.
+        let mut values = Vec::with_capacity(1);
+        loop {
+            self.skip_whitespace(); // Unnecessary for correctness, but may help try() in parse_one rewind less.
+            match self.parse_until_before(Delimiter::Comma, &mut parse_one) {
+                Ok(v) => values.push(v),
+                Err(e) if !ignore_errors => return Err(e),
+                Err(_) => {}
+            }
+            match self.next() {
+                Err(_) => return Ok(values),
+                Ok(&Token::Comma) => continue,
+                Ok(_) => unreachable!(),
+            }
+        }
+    }
+
+    /// Parse the content of a block or function.
+    ///
+    /// This method panics if the last token yielded by this parser
+    /// (from one of the `next*` methods)
+    /// is not a on that marks the start of a block or function:
+    /// a `Function`, `ParenthesisBlock`, `CurlyBracketBlock`, or `SquareBracketBlock`.
+    ///
+    /// The given closure is called with a "delimited" parser
+    /// that stops at the end of the block or function (at the matching closing token).
+    ///
+    /// The result is overridden to an `Err(..)` if the closure leaves some input before that point.
+    #[inline]
+    pub fn parse_nested_block<F, T, E>(&mut self, parse: F) -> Result<T, ParseError<'i, E>>
+    where
+        F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        parse_nested_block(self, parse)
+    }
+
+    /// Limit parsing to until a given delimiter or the end of the input. (E.g.
+    /// a semicolon for a property value.)
+    ///
+    /// The given closure is called with a "delimited" parser
+    /// that stops before the first character at this block/function nesting level
+    /// that matches the given set of delimiters, or at the end of the input.
+    ///
+    /// The result is overridden to an `Err(..)` if the closure leaves some input before that point.
+    #[inline]
+    pub fn parse_until_before<F, T, E>(
+        &mut self,
+        delimiters: Delimiters,
+        parse: F,
+    ) -> Result<T, ParseError<'i, E>>
+    where
+        F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        parse_until_before(self, delimiters, ParseUntilErrorBehavior::Consume, parse)
+    }
+
+    /// Like `parse_until_before`, but also consume the delimiter token.
+    ///
+    /// This can be useful when you don’t need to know which delimiter it was
+    /// (e.g. if these is only one in the given set)
+    /// or if it was there at all (as opposed to reaching the end of the input).
+    #[inline]
+    pub fn parse_until_after<F, T, E>(
+        &mut self,
+        delimiters: Delimiters,
+        parse: F,
+    ) -> Result<T, ParseError<'i, E>>
+    where
+        F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+    {
+        parse_until_after(self, delimiters, ParseUntilErrorBehavior::Consume, parse)
+    }
+
+    /// Parse a <whitespace-token> and return its value.
+    #[inline]
+    pub fn expect_whitespace(&mut self) -> Result<&'i str, BasicParseError<'i>> {
+        let start_location = self.current_source_location();
+        match *self.next_including_whitespace()? {
+            Token::WhiteSpace(value) => Ok(value),
+            ref t => Err(start_location.new_basic_unexpected_token_error(t.clone())),
+        }
+    }
+
+    /// Parse a <ident-token> and return the unescaped value.
+    #[inline]
+    pub fn expect_ident(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::Ident(ref value) => Ok(value),
+        }
+    }
+
+    /// expect_ident, but clone the CowRcStr
+    #[inline]
+    pub fn expect_ident_cloned(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
+        self.expect_ident().cloned()
+    }
+
+    /// Parse a <ident-token> whose unescaped value is an ASCII-insensitive match for the given value.
+    #[inline]
+    pub fn expect_ident_matching(
+        &mut self,
+        expected_value: &str,
+    ) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Ident(ref value) if value.eq_ignore_ascii_case(expected_value) => Ok(()),
+        }
+    }
+
+    /// Parse a <string-token> and return the unescaped value.
+    #[inline]
+    pub fn expect_string(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::QuotedString(ref value) => Ok(value),
+        }
+    }
+
+    /// expect_string, but clone the CowRcStr
+    #[inline]
+    pub fn expect_string_cloned(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
+        self.expect_string().cloned()
+    }
+
+    /// Parse either a <ident-token> or a <string-token>, and return the unescaped value.
+    #[inline]
+    pub fn expect_ident_or_string(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::Ident(ref value) => Ok(value),
+            Token::QuotedString(ref value) => Ok(value),
+        }
+    }
+
+    /// Parse a <url-token> and return the unescaped value.
+    #[inline]
+    pub fn expect_url(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::UnquotedUrl(ref value) => Ok(value.clone()),
+            Token::Function(ref name) if name.eq_ignore_ascii_case("url") => {
+                self.parse_nested_block(|input| {
+                    input.expect_string().map_err(Into::into).cloned()
+                })
+                .map_err(ParseError::<()>::basic)
+            }
+        }
+    }
+
+    /// Parse either a <url-token> or a <string-token>, and return the unescaped value.
+    #[inline]
+    pub fn expect_url_or_string(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::UnquotedUrl(ref value) => Ok(value.clone()),
+            Token::QuotedString(ref value) => Ok(value.clone()),
+            Token::Function(ref name) if name.eq_ignore_ascii_case("url") => {
+                self.parse_nested_block(|input| {
+                    input.expect_string().map_err(Into::into).cloned()
+                })
+                .map_err(ParseError::<()>::basic)
+            }
+        }
+    }
+
+    /// Parse a <number-token> and return the integer value.
+    #[inline]
+    pub fn expect_number(&mut self) -> Result<f32, BasicParseError<'i>> {
+        expect! {self,
+            Token::Number { value, .. } => Ok(value),
+        }
+    }
+
+    /// Parse a <number-token> that does not have a fractional part, and return the integer value.
+    #[inline]
+    pub fn expect_integer(&mut self) -> Result<i32, BasicParseError<'i>> {
+        expect! {self,
+            Token::Number { int_value: Some(int_value), .. } => Ok(int_value),
+        }
+    }
+
+    /// Parse a <percentage-token> and return the value.
+    /// `0%` and `100%` map to `0.0` and `1.0` (not `100.0`), respectively.
+    #[inline]
+    pub fn expect_percentage(&mut self) -> Result<f32, BasicParseError<'i>> {
+        expect! {self,
+            Token::Percentage { unit_value, .. } => Ok(unit_value),
+        }
+    }
+
+    /// Parse a `:` <colon-token>.
+    #[inline]
+    pub fn expect_colon(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Colon => Ok(()),
+        }
+    }
+
+    /// Parse a `;` <semicolon-token>.
+    #[inline]
+    pub fn expect_semicolon(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Semicolon => Ok(()),
+        }
+    }
+
+    /// Parse a `,` <comma-token>.
+    #[inline]
+    pub fn expect_comma(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Comma => Ok(()),
+        }
+    }
+
+    /// Parse a <delim-token> with the given value.
+    #[inline]
+    pub fn expect_delim(&mut self, expected_value: char) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Delim(value) if value == expected_value => Ok(()),
+        }
+    }
+
+    /// Parse a `{ /* ... */ }` curly brackets block.
+    ///
+    /// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
+    #[inline]
+    pub fn expect_curly_bracket_block(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::CurlyBracketBlock => Ok(()),
+        }
+    }
+
+    /// Parse a `[ /* ... */ ]` square brackets block.
+    ///
+    /// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
+    #[inline]
+    pub fn expect_square_bracket_block(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::SquareBracketBlock => Ok(()),
+        }
+    }
+
+    /// Parse a `( /* ... */ )` parenthesis block.
+    ///
+    /// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
+    #[inline]
+    pub fn expect_parenthesis_block(&mut self) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::ParenthesisBlock => Ok(()),
+        }
+    }
+
+    /// Parse a <function> token and return its name.
+    ///
+    /// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
+    #[inline]
+    pub fn expect_function(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
+        expect! {self,
+            Token::Function(ref name) => Ok(name),
+        }
+    }
+
+    /// Parse a <function> token whose name is an ASCII-insensitive match for the given value.
+    ///
+    /// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
+    #[inline]
+    pub fn expect_function_matching(
+        &mut self,
+        expected_name: &str,
+    ) -> Result<(), BasicParseError<'i>> {
+        expect! {self,
+            Token::Function(ref name) if name.eq_ignore_ascii_case(expected_name) => Ok(()),
+        }
+    }
+
+    /// Parse the input until exhaustion and check that it contains no “error” token.
+    ///
+    /// See `Token::is_parse_error`. This also checks nested blocks and functions recursively.
+    #[inline]
+    pub fn expect_no_error_token(&mut self) -> Result<(), BasicParseError<'i>> {
+        loop {
+            match self.next_including_whitespace_and_comments() {
+                Ok(&Token::Function(_))
+                | Ok(&Token::ParenthesisBlock)
+                | Ok(&Token::SquareBracketBlock)
+                | Ok(&Token::CurlyBracketBlock) => self
+                    .parse_nested_block(|input| input.expect_no_error_token().map_err(Into::into))
+                    .map_err(ParseError::<()>::basic)?,
+                Ok(t) => {
+                    // FIXME: maybe these should be separate variants of
+                    // BasicParseError instead?
+                    if t.is_parse_error() {
+                        let token = t.clone();
+                        return Err(self.new_basic_unexpected_token_error(token));
+                    }
+                }
+                Err(_) => return Ok(()),
+            }
+        }
+    }
+}
+
+pub fn parse_until_before<'i: 't, 't, F, T, E>(
+    parser: &mut Parser<'i, 't>,
+    delimiters: Delimiters,
+    error_behavior: ParseUntilErrorBehavior,
+    parse: F,
+) -> Result<T, ParseError<'i, E>>
+where
+    F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+{
+    let delimiters = parser.stop_before | delimiters;
+    let result;
+    // Introduce a new scope to limit duration of nested_parser’s borrow
+    {
+        let mut delimited_parser = Parser {
+            input: parser.input,
+            at_start_of: parser.at_start_of.take(),
+            stop_before: delimiters,
+        };
+        result = delimited_parser.parse_entirely(parse);
+        if error_behavior == ParseUntilErrorBehavior::Stop && result.is_err() {
+            return result;
+        }
+        if let Some(block_type) = delimited_parser.at_start_of {
+            consume_until_end_of_block(block_type, &mut delimited_parser.input.tokenizer);
+        }
+    }
+    // FIXME: have a special-purpose tokenizer method for this that does less work.
+    loop {
+        if delimiters.contains(Delimiters::from_byte(parser.input.tokenizer.next_byte())) {
+            break;
+        }
+        if let Ok(token) = parser.input.tokenizer.next() {
+            if let Some(block_type) = BlockType::opening(&token) {
+                consume_until_end_of_block(block_type, &mut parser.input.tokenizer);
+            }
+        } else {
+            break;
+        }
+    }
+    result
+}
+
+pub fn parse_until_after<'i: 't, 't, F, T, E>(
+    parser: &mut Parser<'i, 't>,
+    delimiters: Delimiters,
+    error_behavior: ParseUntilErrorBehavior,
+    parse: F,
+) -> Result<T, ParseError<'i, E>>
+where
+    F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+{
+    let result = parse_until_before(parser, delimiters, error_behavior, parse);
+    if error_behavior == ParseUntilErrorBehavior::Stop && result.is_err() {
+        return result;
+    }
+    let next_byte = parser.input.tokenizer.next_byte();
+    if next_byte.is_some()
+        && !parser
+            .stop_before
+            .contains(Delimiters::from_byte(next_byte))
+    {
+        debug_assert!(delimiters.contains(Delimiters::from_byte(next_byte)));
+        // We know this byte is ASCII.
+        parser.input.tokenizer.advance(1);
+        if next_byte == Some(b'{') {
+            consume_until_end_of_block(BlockType::CurlyBracket, &mut parser.input.tokenizer);
+        }
+    }
+    result
+}
+
+pub fn parse_nested_block<'i: 't, 't, F, T, E>(
+    parser: &mut Parser<'i, 't>,
+    parse: F,
+) -> Result<T, ParseError<'i, E>>
+where
+    F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
+{
+    let block_type = parser.at_start_of.take().expect(
+        "\
+         A nested parser can only be created when a Function, \
+         ParenthesisBlock, SquareBracketBlock, or CurlyBracketBlock \
+         token was just consumed.\
+         ",
+    );
+    let closing_delimiter = match block_type {
+        BlockType::CurlyBracket => ClosingDelimiter::CloseCurlyBracket,
+        BlockType::SquareBracket => ClosingDelimiter::CloseSquareBracket,
+        BlockType::Parenthesis => ClosingDelimiter::CloseParenthesis,
+    };
+    let result;
+    // Introduce a new scope to limit duration of nested_parser’s borrow
+    {
+        let mut nested_parser = Parser {
+            input: parser.input,
+            at_start_of: None,
+            stop_before: closing_delimiter,
+        };
+        result = nested_parser.parse_entirely(parse);
+        if let Some(block_type) = nested_parser.at_start_of {
+            consume_until_end_of_block(block_type, &mut nested_parser.input.tokenizer);
+        }
+    }
+    consume_until_end_of_block(block_type, &mut parser.input.tokenizer);
+    result
+}
+
+#[inline(never)]
+#[cold]
+fn consume_until_end_of_block(block_type: BlockType, tokenizer: &mut Tokenizer) {
+    let mut stack = SmallVec::<[BlockType; 16]>::new();
+    stack.push(block_type);
+
+    // FIXME: have a special-purpose tokenizer method for this that does less work.
+    while let Ok(ref token) = tokenizer.next() {
+        if let Some(b) = BlockType::closing(token) {
+            if *stack.last().unwrap() == b {
+                stack.pop();
+                if stack.is_empty() {
+                    return;
+                }
+            }
+        }
+
+        if let Some(block_type) = BlockType::opening(token) {
+            stack.push(block_type);
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/rules_and_declarations.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/rules_and_declarations.rs
new file mode 100644
index 000000000000..48da02b5cc73
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/rules_and_declarations.rs
@@ -0,0 +1,538 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://drafts.csswg.org/css-syntax/#parsing
+
+use super::{BasicParseError, BasicParseErrorKind, Delimiter, ParseError, Parser, Token};
+use crate::cow_rc_str::CowRcStr;
+use crate::parser::{parse_nested_block, parse_until_after, ParseUntilErrorBehavior, ParserState};
+
+/// Parse `!important`.
+///
+/// Typical usage is `input.try_parse(parse_important).is_ok()`
+/// at the end of a `DeclarationParser::parse_value` implementation.
+pub fn parse_important<'i>(input: &mut Parser<'i, '_>) -> Result<(), BasicParseError<'i>> {
+    input.expect_delim('!')?;
+    input.expect_ident_matching("important")
+}
+
+/// A trait to provide various parsing of declaration values.
+///
+/// For example, there could be different implementations for property declarations in style rules
+/// and for descriptors in `@font-face` rules.
+pub trait DeclarationParser<'i> {
+    /// The finished representation of a declaration.
+    type Declaration;
+
+    /// The error type that is included in the ParseError value that can be returned.
+    type Error: 'i;
+
+    /// Parse the value of a declaration with the given `name`.
+    ///
+    /// Return the finished representation for the declaration
+    /// as returned by `DeclarationListParser::next`,
+    /// or an `Err(..)` to ignore the entire declaration as invalid.
+    ///
+    /// Declaration name matching should be case-insensitive in the ASCII range.
+    /// This can be done with `std::ascii::Ascii::eq_ignore_ascii_case`,
+    /// or with the `match_ignore_ascii_case!` macro.
+    ///
+    /// The given `input` is a "delimited" parser
+    /// that ends wherever the declaration value should end.
+    /// (In declaration lists, before the next semicolon or end of the current block.)
+    ///
+    /// If `!important` can be used in a given context,
+    /// `input.try_parse(parse_important).is_ok()` should be used at the end
+    /// of the implementation of this method and the result should be part of the return value.
+    fn parse_value<'t>(
+        &mut self,
+        name: CowRcStr<'i>,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self::Declaration, ParseError<'i, Self::Error>> {
+        Err(input.new_error(BasicParseErrorKind::UnexpectedToken(Token::Ident(name))))
+    }
+}
+
+/// A trait to provide various parsing of at-rules.
+///
+/// For example, there could be different implementations for top-level at-rules
+/// (`@media`, `@font-face`, …)
+/// and for page-margin rules inside `@page`.
+///
+/// Default implementations that reject all at-rules are provided,
+/// so that `impl AtRuleParser<(), ()> for ... {}` can be used
+/// for using `DeclarationListParser` to parse a declarations list with only qualified rules.
+pub trait AtRuleParser<'i> {
+    /// The intermediate representation of prelude of an at-rule.
+    type Prelude;
+
+    /// The finished representation of an at-rule.
+    type AtRule;
+
+    /// The error type that is included in the ParseError value that can be returned.
+    type Error: 'i;
+
+    /// Parse the prelude of an at-rule with the given `name`.
+    ///
+    /// Return the representation of the prelude and the type of at-rule,
+    /// or an `Err(..)` to ignore the entire at-rule as invalid.
+    ///
+    /// The prelude is the part after the at-keyword
+    /// and before the `;` semicolon or `{ /* ... */ }` block.
+    ///
+    /// At-rule name matching should be case-insensitive in the ASCII range.
+    /// This can be done with `std::ascii::Ascii::eq_ignore_ascii_case`,
+    /// or with the `match_ignore_ascii_case!` macro.
+    ///
+    /// The given `input` is a "delimited" parser
+    /// that ends wherever the prelude should end.
+    /// (Before the next semicolon, the next `{`, or the end of the current block.)
+    fn parse_prelude<'t>(
+        &mut self,
+        name: CowRcStr<'i>,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self::Prelude, ParseError<'i, Self::Error>> {
+        Err(input.new_error(BasicParseErrorKind::AtRuleInvalid(name)))
+    }
+
+    /// End an at-rule which doesn't have block. Return the finished
+    /// representation of the at-rule.
+    ///
+    /// The location passed in is source location of the start of the prelude.
+    ///
+    /// This is only called when `parse_prelude` returned `WithoutBlock`, and
+    /// either the `;` semicolon indeed follows the prelude, or parser is at
+    /// the end of the input.
+    #[allow(clippy::result_unit_err)]
+    fn rule_without_block(
+        &mut self,
+        prelude: Self::Prelude,
+        start: &ParserState,
+    ) -> Result<Self::AtRule, ()> {
+        let _ = prelude;
+        let _ = start;
+        Err(())
+    }
+
+    /// Parse the content of a `{ /* ... */ }` block for the body of the at-rule.
+    ///
+    /// The location passed in is source location of the start of the prelude.
+    ///
+    /// Return the finished representation of the at-rule
+    /// as returned by `RuleListParser::next` or `DeclarationListParser::next`,
+    /// or an `Err(..)` to ignore the entire at-rule as invalid.
+    ///
+    /// This is only called when `parse_prelude` returned `WithBlock`, and a block
+    /// was indeed found following the prelude.
+    fn parse_block<'t>(
+        &mut self,
+        prelude: Self::Prelude,
+        start: &ParserState,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
+        let _ = prelude;
+        let _ = start;
+        Err(input.new_error(BasicParseErrorKind::AtRuleBodyInvalid))
+    }
+}
+
+/// A trait to provide various parsing of qualified rules.
+///
+/// For example, there could be different implementations for top-level qualified rules (i.e. style
+/// rules with Selectors as prelude) and for qualified rules inside `@keyframes` (keyframe rules
+/// with keyframe selectors as prelude).
+///
+/// Default implementations that reject all qualified rules are provided, so that
+/// `impl QualifiedRuleParser<(), ()> for ... {}` can be used for example for using
+/// `RuleListParser` to parse a rule list with only at-rules (such as inside
+/// `@font-feature-values`).
+pub trait QualifiedRuleParser<'i> {
+    /// The intermediate representation of a qualified rule prelude.
+    type Prelude;
+
+    /// The finished representation of a qualified rule.
+    type QualifiedRule;
+
+    /// The error type that is included in the ParseError value that can be returned.
+    type Error: 'i;
+
+    /// Parse the prelude of a qualified rule. For style rules, this is as Selector list.
+    ///
+    /// Return the representation of the prelude,
+    /// or an `Err(..)` to ignore the entire at-rule as invalid.
+    ///
+    /// The prelude is the part before the `{ /* ... */ }` block.
+    ///
+    /// The given `input` is a "delimited" parser
+    /// that ends where the prelude should end (before the next `{`).
+    fn parse_prelude<'t>(
+        &mut self,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self::Prelude, ParseError<'i, Self::Error>> {
+        Err(input.new_error(BasicParseErrorKind::QualifiedRuleInvalid))
+    }
+
+    /// Parse the content of a `{ /* ... */ }` block for the body of the qualified rule.
+    ///
+    /// The location passed in is source location of the start of the prelude.
+    ///
+    /// Return the finished representation of the qualified rule
+    /// as returned by `RuleListParser::next`,
+    /// or an `Err(..)` to ignore the entire at-rule as invalid.
+    fn parse_block<'t>(
+        &mut self,
+        prelude: Self::Prelude,
+        start: &ParserState,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self::QualifiedRule, ParseError<'i, Self::Error>> {
+        let _ = prelude;
+        let _ = start;
+        Err(input.new_error(BasicParseErrorKind::QualifiedRuleInvalid))
+    }
+}
+
+/// Provides an iterator for rule bodies and declaration lists.
+pub struct RuleBodyParser<'i, 't, 'a, P, I, E> {
+    /// The input given to the parser.
+    pub input: &'a mut Parser<'i, 't>,
+    /// The parser given to `DeclarationListParser::new`
+    pub parser: &'a mut P,
+
+    _phantom: std::marker::PhantomData<(I, E)>,
+}
+
+/// A parser for a rule body item.
+pub trait RuleBodyItemParser<'i, DeclOrRule, Error: 'i>:
+    DeclarationParser<'i, Declaration = DeclOrRule, Error = Error>
+    + QualifiedRuleParser<'i, QualifiedRule = DeclOrRule, Error = Error>
+    + AtRuleParser<'i, AtRule = DeclOrRule, Error = Error>
+{
+    /// Whether we should attempt to parse declarations. If you know you won't, returning false
+    /// here is slightly faster.
+    fn parse_declarations(&self) -> bool;
+    /// Whether we should attempt to parse qualified rules. If you know you won't, returning false
+    /// would be slightly faster.
+    fn parse_qualified(&self) -> bool;
+}
+
+impl<'i, 't, 'a, P, I, E> RuleBodyParser<'i, 't, 'a, P, I, E> {
+    /// Create a new `DeclarationListParser` for the given `input` and `parser`.
+    ///
+    /// Note that all CSS declaration lists can on principle contain at-rules.
+    /// Even if no such valid at-rule exists (yet),
+    /// this affects error handling: at-rules end at `{}` blocks, not just semicolons.
+    ///
+    /// The given `parser` therefore needs to implement
+    /// both `DeclarationParser` and `AtRuleParser` traits.
+    /// However, the latter can be an empty `impl`
+    /// since `AtRuleParser` provides default implementations of its methods.
+    ///
+    /// The return type for finished declarations and at-rules also needs to be the same,
+    /// since `<DeclarationListParser as Iterator>::next` can return either.
+    /// It could be a custom enum.
+    pub fn new(input: &'a mut Parser<'i, 't>, parser: &'a mut P) -> Self {
+        Self {
+            input,
+            parser,
+            _phantom: std::marker::PhantomData,
+        }
+    }
+}
+
+/// https://drafts.csswg.org/css-syntax/#consume-a-blocks-contents
+impl<'i, 't, 'a, I, P, E: 'i> Iterator for RuleBodyParser<'i, 't, 'a, P, I, E>
+where
+    P: RuleBodyItemParser<'i, I, E>,
+{
+    type Item = Result<I, (ParseError<'i, E>, &'i str)>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            self.input.skip_whitespace();
+            let start = self.input.state();
+            match self.input.next_including_whitespace_and_comments().ok()? {
+                Token::CloseCurlyBracket
+                | Token::WhiteSpace(..)
+                | Token::Semicolon
+                | Token::Comment(..) => continue,
+                Token::AtKeyword(ref name) => {
+                    let name = name.clone();
+                    return Some(parse_at_rule(&start, name, self.input, &mut *self.parser));
+                }
+                // https://drafts.csswg.org/css-syntax/#consume-a-declaration bails out just to
+                // keep parsing as a qualified rule if the token is not an ident, so we implement
+                // that in a slightly more straight-forward way
+                Token::Ident(ref name) if self.parser.parse_declarations() => {
+                    let name = name.clone();
+                    let parse_qualified = self.parser.parse_qualified();
+                    let result = {
+                        let error_behavior = if parse_qualified {
+                            ParseUntilErrorBehavior::Stop
+                        } else {
+                            ParseUntilErrorBehavior::Consume
+                        };
+                        let parser = &mut self.parser;
+                        parse_until_after(
+                            self.input,
+                            Delimiter::Semicolon,
+                            error_behavior,
+                            |input| {
+                                input.expect_colon()?;
+                                parser.parse_value(name, input)
+                            },
+                        )
+                    };
+                    if result.is_err() && parse_qualified {
+                        self.input.reset(&start);
+                        // We ignore the resulting error here. The property declaration parse error
+                        // is likely to be more relevant.
+                        if let Ok(qual) = parse_qualified_rule(
+                            &start,
+                            self.input,
+                            &mut *self.parser,
+                            /* nested = */ true,
+                        ) {
+                            return Some(Ok(qual));
+                        }
+                    }
+
+                    return Some(result.map_err(|e| (e, self.input.slice_from(start.position()))));
+                }
+                token => {
+                    let result = if self.parser.parse_qualified() {
+                        self.input.reset(&start);
+                        let nested = self.parser.parse_declarations();
+                        parse_qualified_rule(&start, self.input, &mut *self.parser, nested)
+                    } else {
+                        let token = token.clone();
+                        self.input.parse_until_after(Delimiter::Semicolon, |_| {
+                            Err(start.source_location().new_unexpected_token_error(token))
+                        })
+                    };
+                    return Some(result.map_err(|e| (e, self.input.slice_from(start.position()))));
+                }
+            }
+        }
+    }
+}
+
+/// Provides an iterator for rule list parsing at the top-level of a stylesheet.
+pub struct StyleSheetParser<'i, 't, 'a, P> {
+    /// The input given.
+    pub input: &'a mut Parser<'i, 't>,
+
+    /// The parser given.
+    pub parser: &'a mut P,
+
+    any_rule_so_far: bool,
+}
+
+impl<'i, 't, 'a, R, P, E: 'i> StyleSheetParser<'i, 't, 'a, P>
+where
+    P: QualifiedRuleParser<'i, QualifiedRule = R, Error = E>
+        + AtRuleParser<'i, AtRule = R, Error = E>,
+{
+    /// The given `parser` needs to implement both `QualifiedRuleParser` and `AtRuleParser` traits.
+    /// However, either of them can be an empty `impl` since the traits provide default
+    /// implementations of their methods.
+    ///
+    /// The return type for finished qualified rules and at-rules also needs to be the same,
+    /// since `<RuleListParser as Iterator>::next` can return either. It could be a custom enum.
+    pub fn new(input: &'a mut Parser<'i, 't>, parser: &'a mut P) -> Self {
+        Self {
+            input,
+            parser,
+            any_rule_so_far: false,
+        }
+    }
+}
+
+/// `RuleListParser` is an iterator that yields `Ok(_)` for a rule or an `Err(..)` for an invalid one.
+impl<'i, 't, 'a, R, P, E: 'i> Iterator for StyleSheetParser<'i, 't, 'a, P>
+where
+    P: QualifiedRuleParser<'i, QualifiedRule = R, Error = E>
+        + AtRuleParser<'i, AtRule = R, Error = E>,
+{
+    type Item = Result<R, (ParseError<'i, E>, &'i str)>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            self.input.skip_cdc_and_cdo();
+            let start = self.input.state();
+            let at_keyword = match self.input.next_byte()? {
+                b'@' => match self.input.next_including_whitespace_and_comments() {
+                    Ok(Token::AtKeyword(name)) => Some(name.clone()),
+                    _ => {
+                        self.input.reset(&start);
+                        None
+                    }
+                },
+                _ => None,
+            };
+
+            if let Some(name) = at_keyword {
+                let first_stylesheet_rule = !self.any_rule_so_far;
+                self.any_rule_so_far = true;
+                if first_stylesheet_rule && name.eq_ignore_ascii_case("charset") {
+                    let delimiters = Delimiter::Semicolon | Delimiter::CurlyBracketBlock;
+                    let _: Result<(), ParseError<()>> =
+                        self.input.parse_until_after(delimiters, |_| Ok(()));
+                } else {
+                    return Some(parse_at_rule(
+                        &start,
+                        name.clone(),
+                        self.input,
+                        &mut *self.parser,
+                    ));
+                }
+            } else {
+                self.any_rule_so_far = true;
+                let result = parse_qualified_rule(
+                    &start,
+                    self.input,
+                    &mut *self.parser,
+                    /* nested = */ false,
+                );
+                return Some(result.map_err(|e| (e, self.input.slice_from(start.position()))));
+            }
+        }
+    }
+}
+
+/// Parse a single declaration, such as an `( /* ... */ )` parenthesis in an `@supports` prelude.
+pub fn parse_one_declaration<'i, 't, P, E>(
+    input: &mut Parser<'i, 't>,
+    parser: &mut P,
+) -> Result<<P as DeclarationParser<'i>>::Declaration, (ParseError<'i, E>, &'i str)>
+where
+    P: DeclarationParser<'i, Error = E>,
+{
+    let start_position = input.position();
+    input
+        .parse_entirely(|input| {
+            let name = input.expect_ident()?.clone();
+            input.expect_colon()?;
+            parser.parse_value(name, input)
+        })
+        .map_err(|e| (e, input.slice_from(start_position)))
+}
+
+/// Parse a single rule, such as for CSSOM’s `CSSStyleSheet.insertRule`.
+pub fn parse_one_rule<'i, 't, R, P, E>(
+    input: &mut Parser<'i, 't>,
+    parser: &mut P,
+) -> Result<R, ParseError<'i, E>>
+where
+    P: QualifiedRuleParser<'i, QualifiedRule = R, Error = E>
+        + AtRuleParser<'i, AtRule = R, Error = E>,
+{
+    input.parse_entirely(|input| {
+        input.skip_whitespace();
+        let start = input.state();
+        let at_keyword = if input.next_byte() == Some(b'@') {
+            match *input.next_including_whitespace_and_comments()? {
+                Token::AtKeyword(ref name) => Some(name.clone()),
+                _ => {
+                    input.reset(&start);
+                    None
+                }
+            }
+        } else {
+            None
+        };
+
+        if let Some(name) = at_keyword {
+            parse_at_rule(&start, name, input, parser).map_err(|e| e.0)
+        } else {
+            parse_qualified_rule(&start, input, parser, /* nested = */ false)
+        }
+    })
+}
+
+fn parse_at_rule<'i, 't, P, E>(
+    start: &ParserState,
+    name: CowRcStr<'i>,
+    input: &mut Parser<'i, 't>,
+    parser: &mut P,
+) -> Result<<P as AtRuleParser<'i>>::AtRule, (ParseError<'i, E>, &'i str)>
+where
+    P: AtRuleParser<'i, Error = E>,
+{
+    let delimiters = Delimiter::Semicolon | Delimiter::CurlyBracketBlock;
+    let result = input.parse_until_before(delimiters, |input| parser.parse_prelude(name, input));
+    match result {
+        Ok(prelude) => {
+            let result = match input.next() {
+                Ok(&Token::Semicolon) | Err(_) => parser
+                    .rule_without_block(prelude, start)
+                    .map_err(|()| input.new_unexpected_token_error(Token::Semicolon)),
+                Ok(&Token::CurlyBracketBlock) => {
+                    parse_nested_block(input, |input| parser.parse_block(prelude, start, input))
+                }
+                Ok(_) => unreachable!(),
+            };
+            result.map_err(|e| (e, input.slice_from(start.position())))
+        }
+        Err(error) => {
+            let end_position = input.position();
+            match input.next() {
+                Ok(&Token::CurlyBracketBlock) | Ok(&Token::Semicolon) | Err(_) => {}
+                _ => unreachable!(),
+            };
+            Err((error, input.slice(start.position()..end_position)))
+        }
+    }
+}
+
+//  If the first two non-<whitespace-token> values of rule’s prelude are an <ident-token> whose
+//  value starts with "--" followed by a <colon-token>, then...
+fn looks_like_a_custom_property(input: &mut Parser) -> bool {
+    let ident = match input.expect_ident() {
+        Ok(i) => i,
+        Err(..) => return false,
+    };
+    ident.starts_with("--") && input.expect_colon().is_ok()
+}
+
+// https://drafts.csswg.org/css-syntax/#consume-a-qualified-rule
+fn parse_qualified_rule<'i, 't, P, E>(
+    start: &ParserState,
+    input: &mut Parser<'i, 't>,
+    parser: &mut P,
+    nested: bool,
+) -> Result<<P as QualifiedRuleParser<'i>>::QualifiedRule, ParseError<'i, E>>
+where
+    P: QualifiedRuleParser<'i, Error = E>,
+{
+    input.skip_whitespace();
+    let prelude = {
+        let state = input.state();
+        if looks_like_a_custom_property(input) {
+            // If nested is true, consume the remnants of a bad declaration from input, with
+            // nested set to true, and return nothing.
+            // If nested is false, consume a block from input, and return nothing.
+            let delimiters = if nested {
+                Delimiter::Semicolon
+            } else {
+                Delimiter::CurlyBracketBlock
+            };
+            let _: Result<(), ParseError<()>> = input.parse_until_after(delimiters, |_| Ok(()));
+            return Err(state
+                .source_location()
+                .new_error(BasicParseErrorKind::QualifiedRuleInvalid));
+        }
+        let delimiters = if nested {
+            Delimiter::Semicolon | Delimiter::CurlyBracketBlock
+        } else {
+            Delimiter::CurlyBracketBlock
+        };
+        input.reset(&state);
+        input.parse_until_before(delimiters, |input| parser.parse_prelude(input))
+    };
+
+    input.expect_curly_bracket_block()?;
+    // Do this here so that we consume the `{` even if the prelude is `Err`.
+    let prelude = prelude?;
+    parse_nested_block(input, |input| parser.parse_block(prelude, start, input))
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/serializer.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/serializer.rs
new file mode 100644
index 000000000000..3c6e31cb8422
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/serializer.rs
@@ -0,0 +1,591 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::match_byte;
+use dtoa_short::Notation;
+use std::fmt::{self, Write};
+use std::str;
+
+use super::Token;
+
+/// Trait for things the can serialize themselves in CSS syntax.
+pub trait ToCss {
+    /// Serialize `self` in CSS syntax, writing to `dest`.
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write;
+
+    /// Serialize `self` in CSS syntax and return a string.
+    ///
+    /// (This is a convenience wrapper for `to_css` and probably should not be overridden.)
+    #[inline]
+    fn to_css_string(&self) -> String {
+        let mut s = String::new();
+        self.to_css(&mut s).unwrap();
+        s
+    }
+}
+
+#[inline]
+fn write_numeric<W>(value: f32, int_value: Option<i32>, has_sign: bool, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    // `value.value >= 0` is true for negative 0.
+    if has_sign && value.is_sign_positive() {
+        dest.write_str("+")?;
+    }
+
+    let notation = if value == 0.0 && value.is_sign_negative() {
+        // Negative zero. Work around #20596.
+        dest.write_str("-0")?;
+        Notation {
+            decimal_point: false,
+            scientific: false,
+        }
+    } else {
+        dtoa_short::write(dest, value)?
+    };
+
+    if int_value.is_none() && value.fract() == 0. && !notation.decimal_point && !notation.scientific
+    {
+        dest.write_str(".0")?;
+    }
+    Ok(())
+}
+
+impl<'a> ToCss for Token<'a> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        match *self {
+            Token::Ident(ref value) => serialize_identifier(value, dest)?,
+            Token::AtKeyword(ref value) => {
+                dest.write_str("@")?;
+                serialize_identifier(value, dest)?;
+            }
+            Token::Hash(ref value) => {
+                dest.write_str("#")?;
+                serialize_name(value, dest)?;
+            }
+            Token::IDHash(ref value) => {
+                dest.write_str("#")?;
+                serialize_identifier(value, dest)?;
+            }
+            Token::QuotedString(ref value) => serialize_string(value, dest)?,
+            Token::UnquotedUrl(ref value) => {
+                dest.write_str("url(")?;
+                serialize_unquoted_url(value, dest)?;
+                dest.write_str(")")?;
+            }
+            Token::Delim(value) => dest.write_char(value)?,
+
+            Token::Number {
+                value,
+                int_value,
+                has_sign,
+            } => write_numeric(value, int_value, has_sign, dest)?,
+            Token::Percentage {
+                unit_value,
+                int_value,
+                has_sign,
+            } => {
+                write_numeric(unit_value * 100., int_value, has_sign, dest)?;
+                dest.write_str("%")?;
+            }
+            Token::Dimension {
+                value,
+                int_value,
+                has_sign,
+                ref unit,
+            } => {
+                write_numeric(value, int_value, has_sign, dest)?;
+                // Disambiguate with scientific notation.
+                let unit = &**unit;
+                // TODO(emilio): This doesn't handle e.g. 100E1m, which gets us
+                // an unit of "E1m"...
+                if unit == "e" || unit == "E" || unit.starts_with("e-") || unit.starts_with("E-") {
+                    dest.write_str("\\65 ")?;
+                    serialize_name(&unit[1..], dest)?;
+                } else {
+                    serialize_identifier(unit, dest)?;
+                }
+            }
+
+            Token::WhiteSpace(content) => dest.write_str(content)?,
+            Token::Comment(content) => {
+                dest.write_str("/*")?;
+                dest.write_str(content)?;
+                dest.write_str("*/")?
+            }
+            Token::Colon => dest.write_str(":")?,
+            Token::Semicolon => dest.write_str(";")?,
+            Token::Comma => dest.write_str(",")?,
+            Token::IncludeMatch => dest.write_str("~=")?,
+            Token::DashMatch => dest.write_str("|=")?,
+            Token::PrefixMatch => dest.write_str("^=")?,
+            Token::SuffixMatch => dest.write_str("$=")?,
+            Token::SubstringMatch => dest.write_str("*=")?,
+            Token::CDO => dest.write_str("<!--")?,
+            Token::CDC => dest.write_str("-->")?,
+
+            Token::Function(ref name) => {
+                serialize_identifier(name, dest)?;
+                dest.write_str("(")?;
+            }
+            Token::ParenthesisBlock => dest.write_str("(")?,
+            Token::SquareBracketBlock => dest.write_str("[")?,
+            Token::CurlyBracketBlock => dest.write_str("{")?,
+
+            Token::BadUrl(ref contents) => {
+                dest.write_str("url(")?;
+                dest.write_str(contents)?;
+                dest.write_char(')')?;
+            }
+            Token::BadString(ref value) => {
+                // During tokenization, an unescaped newline after a quote causes
+                // the token to be a BadString instead of a QuotedString.
+                // The BadString token ends just before the newline
+                // (which is in a separate WhiteSpace token),
+                // and therefore does not have a closing quote.
+                dest.write_char('"')?;
+                CssStringWriter::new(dest).write_str(value)?;
+            }
+            Token::CloseParenthesis => dest.write_str(")")?,
+            Token::CloseSquareBracket => dest.write_str("]")?,
+            Token::CloseCurlyBracket => dest.write_str("}")?,
+        }
+        Ok(())
+    }
+}
+
+fn hex_escape<W>(ascii_byte: u8, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    static HEX_DIGITS: &[u8; 16] = b"0123456789abcdef";
+    let b3;
+    let b4;
+    let bytes = if ascii_byte > 0x0F {
+        let high = (ascii_byte >> 4) as usize;
+        let low = (ascii_byte & 0x0F) as usize;
+        b4 = [b'\\', HEX_DIGITS[high], HEX_DIGITS[low], b' '];
+        &b4[..]
+    } else {
+        b3 = [b'\\', HEX_DIGITS[ascii_byte as usize], b' '];
+        &b3[..]
+    };
+    dest.write_str(unsafe { str::from_utf8_unchecked(bytes) })
+}
+
+fn char_escape<W>(ascii_byte: u8, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    let bytes = [b'\\', ascii_byte];
+    dest.write_str(unsafe { str::from_utf8_unchecked(&bytes) })
+}
+
+/// Write a CSS identifier, escaping characters as necessary.
+pub fn serialize_identifier<W>(mut value: &str, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    if value.is_empty() {
+        return Ok(());
+    }
+
+    if let Some(value) = value.strip_prefix("--") {
+        dest.write_str("--")?;
+        serialize_name(value, dest)
+    } else if value == "-" {
+        dest.write_str("\\-")
+    } else {
+        if value.as_bytes()[0] == b'-' {
+            dest.write_str("-")?;
+            value = &value[1..];
+        }
+        if let digit @ b'0'..=b'9' = value.as_bytes()[0] {
+            hex_escape(digit, dest)?;
+            value = &value[1..];
+        }
+        serialize_name(value, dest)
+    }
+}
+
+/// Write a CSS name, like a custom property name.
+///
+/// You should only use this when you know what you're doing, when in doubt,
+/// consider using `serialize_identifier`.
+pub fn serialize_name<W>(value: &str, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    let mut chunk_start = 0;
+    for (i, b) in value.bytes().enumerate() {
+        let escaped = match_byte! { b,
+            b'0'..=b'9' | b'A'..=b'Z' | b'a'..=b'z' | b'_' | b'-' => continue,
+            b'\0' => Some("\u{FFFD}"),
+            b => {
+                if !b.is_ascii() {
+                    continue;
+                }
+                None
+            },
+        };
+        dest.write_str(&value[chunk_start..i])?;
+        if let Some(escaped) = escaped {
+            dest.write_str(escaped)?;
+        } else if (b'\x01'..=b'\x1F').contains(&b) || b == b'\x7F' {
+            hex_escape(b, dest)?;
+        } else {
+            char_escape(b, dest)?;
+        }
+        chunk_start = i + 1;
+    }
+    dest.write_str(&value[chunk_start..])
+}
+
+fn serialize_unquoted_url<W>(value: &str, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    let mut chunk_start = 0;
+    for (i, b) in value.bytes().enumerate() {
+        let hex = match_byte! { b,
+            b'\0'..=b' ' | b'\x7F' => true,
+            b'(' | b')' | b'"' | b'\'' | b'\\' => false,
+            _ => continue,
+        };
+        dest.write_str(&value[chunk_start..i])?;
+        if hex {
+            hex_escape(b, dest)?;
+        } else {
+            char_escape(b, dest)?;
+        }
+        chunk_start = i + 1;
+    }
+    dest.write_str(&value[chunk_start..])
+}
+
+/// Write a double-quoted CSS string token, escaping content as necessary.
+pub fn serialize_string<W>(value: &str, dest: &mut W) -> fmt::Result
+where
+    W: fmt::Write,
+{
+    dest.write_str("\"")?;
+    CssStringWriter::new(dest).write_str(value)?;
+    dest.write_str("\"")?;
+    Ok(())
+}
+
+/// A `fmt::Write` adapter that escapes text for writing as a double-quoted CSS string.
+/// Quotes are not included.
+///
+/// Typical usage:
+///
+/// ```{rust,ignore}
+/// fn write_foo<W>(foo: &Foo, dest: &mut W) -> fmt::Result where W: fmt::Write {
+///     dest.write_str("\"")?;
+///     {
+///         let mut string_dest = CssStringWriter::new(dest);
+///         // Write into string_dest...
+///     }
+///     dest.write_str("\"")?;
+///     Ok(())
+/// }
+/// ```
+pub struct CssStringWriter<'a, W> {
+    inner: &'a mut W,
+}
+
+impl<'a, W> CssStringWriter<'a, W>
+where
+    W: fmt::Write,
+{
+    /// Wrap a text writer to create a `CssStringWriter`.
+    pub fn new(inner: &'a mut W) -> CssStringWriter<'a, W> {
+        CssStringWriter { inner }
+    }
+}
+
+impl<'a, W> fmt::Write for CssStringWriter<'a, W>
+where
+    W: fmt::Write,
+{
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        let mut chunk_start = 0;
+        for (i, b) in s.bytes().enumerate() {
+            let escaped = match_byte! { b,
+                b'"' => Some("\\\""),
+                b'\\' => Some("\\\\"),
+                b'\0' => Some("\u{FFFD}"),
+                b'\x01'..=b'\x1F' | b'\x7F' => None,
+                _ => continue,
+            };
+            self.inner.write_str(&s[chunk_start..i])?;
+            match escaped {
+                Some(x) => self.inner.write_str(x)?,
+                None => hex_escape(b, self.inner)?,
+            };
+            chunk_start = i + 1;
+        }
+        self.inner.write_str(&s[chunk_start..])
+    }
+}
+
+macro_rules! impl_tocss_for_int {
+    ($T: ty) => {
+        impl ToCss for $T {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+            where
+                W: fmt::Write,
+            {
+                let mut buf = itoa::Buffer::new();
+                dest.write_str(buf.format(*self))
+            }
+        }
+    };
+}
+
+impl_tocss_for_int!(i8);
+impl_tocss_for_int!(u8);
+impl_tocss_for_int!(i16);
+impl_tocss_for_int!(u16);
+impl_tocss_for_int!(i32);
+impl_tocss_for_int!(u32);
+impl_tocss_for_int!(i64);
+impl_tocss_for_int!(u64);
+
+macro_rules! impl_tocss_for_float {
+    ($T: ty) => {
+        impl ToCss for $T {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+            where
+                W: fmt::Write,
+            {
+                dtoa_short::write(dest, *self).map(|_| ())
+            }
+        }
+    };
+}
+
+impl_tocss_for_float!(f32);
+impl_tocss_for_float!(f64);
+
+/// A category of token. See the `needs_separator_when_before` method.
+#[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
+pub enum TokenSerializationType {
+    /// No token serialization type.
+    #[default]
+    Nothing,
+
+    /// The [`<whitespace-token>`](https://drafts.csswg.org/css-syntax/#whitespace-token-diagram)
+    /// type.
+    WhiteSpace,
+
+    /// The [`<at-keyword-token>`](https://drafts.csswg.org/css-syntax/#at-keyword-token-diagram)
+    /// type, the "[`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with
+    /// the type flag set to 'unrestricted'" type, or the
+    /// "[`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with the type
+    /// flag set to 'id'" type.
+    AtKeywordOrHash,
+
+    /// The [`<number-token>`](https://drafts.csswg.org/css-syntax/#number-token-diagram) type.
+    Number,
+
+    /// The [`<dimension-token>`](https://drafts.csswg.org/css-syntax/#dimension-token-diagram)
+    /// type.
+    Dimension,
+
+    /// The [`<percentage-token>`](https://drafts.csswg.org/css-syntax/#percentage-token-diagram)
+    /// type.
+    Percentage,
+
+    /// The [`<url-token>`](https://drafts.csswg.org/css-syntax/#url-token-diagram) or
+    /// `<bad-url-token>` type.
+    UrlOrBadUrl,
+
+    /// The [`<function-token>`](https://drafts.csswg.org/css-syntax/#function-token-diagram) type.
+    Function,
+
+    /// The [`<ident-token>`](https://drafts.csswg.org/css-syntax/#ident-token-diagram) type.
+    Ident,
+
+    /// The `-->` [`<CDC-token>`](https://drafts.csswg.org/css-syntax/#CDC-token-diagram) type.
+    CDC,
+
+    /// The `|=`
+    /// [`<dash-match-token>`](https://drafts.csswg.org/css-syntax/#dash-match-token-diagram) type.
+    DashMatch,
+
+    /// The `*=`
+    /// [`<substring-match-token>`](https://drafts.csswg.org/css-syntax/#substring-match-token-diagram)
+    /// type.
+    SubstringMatch,
+
+    /// The `<(-token>` type.
+    OpenParen,
+
+    /// The `#` `<delim-token>` type.
+    DelimHash,
+
+    /// The `@` `<delim-token>` type.
+    DelimAt,
+
+    /// The `.` or `+` `<delim-token>` type.
+    DelimDotOrPlus,
+
+    /// The `-` `<delim-token>` type.
+    DelimMinus,
+
+    /// The `?` `<delim-token>` type.
+    DelimQuestion,
+
+    /// The `$`, `^`, or `~` `<delim-token>` type.
+    DelimAssorted,
+
+    /// The `=` `<delim-token>` type.
+    DelimEquals,
+
+    /// The `|` `<delim-token>` type.
+    DelimBar,
+
+    /// The `/` `<delim-token>` type.
+    DelimSlash,
+
+    /// The `*` `<delim-token>` type.
+    DelimAsterisk,
+
+    /// The `%` `<delim-token>` type.
+    DelimPercent,
+
+    /// A type indicating any other token.
+    Other,
+}
+
+impl TokenSerializationType {
+    /// Return a value that represents the absence of a token, e.g. before the start of the input.
+    #[deprecated(
+        since = "0.32.1",
+        note = "use TokenSerializationType::Nothing or TokenSerializationType::default() instead"
+    )]
+    pub fn nothing() -> TokenSerializationType {
+        Default::default()
+    }
+
+    /// If this value is `TokenSerializationType::Nothing`, set it to the given value instead.
+    pub fn set_if_nothing(&mut self, new_value: TokenSerializationType) {
+        if matches!(self, TokenSerializationType::Nothing) {
+            *self = new_value
+        }
+    }
+
+    /// Return true if, when a token of category `self` is serialized just before
+    /// a token of category `other` with no whitespace in between,
+    /// an empty comment `/**/` needs to be inserted between them
+    /// so that they are not re-parsed as a single token.
+    ///
+    /// See https://drafts.csswg.org/css-syntax/#serialization
+    ///
+    /// See https://github.com/w3c/csswg-drafts/issues/4088 for the
+    /// `DelimPercent` bits.
+    pub fn needs_separator_when_before(self, other: TokenSerializationType) -> bool {
+        use self::TokenSerializationType::*;
+        match self {
+            Ident => matches!(
+                other,
+                Ident
+                    | Function
+                    | UrlOrBadUrl
+                    | DelimMinus
+                    | Number
+                    | Percentage
+                    | Dimension
+                    | CDC
+                    | OpenParen
+            ),
+            AtKeywordOrHash | Dimension => matches!(
+                other,
+                Ident | Function | UrlOrBadUrl | DelimMinus | Number | Percentage | Dimension | CDC
+            ),
+            DelimHash | DelimMinus => matches!(
+                other,
+                Ident | Function | UrlOrBadUrl | DelimMinus | Number | Percentage | Dimension
+            ),
+            Number => matches!(
+                other,
+                Ident
+                    | Function
+                    | UrlOrBadUrl
+                    | DelimMinus
+                    | Number
+                    | Percentage
+                    | DelimPercent
+                    | Dimension
+            ),
+            DelimAt => matches!(other, Ident | Function | UrlOrBadUrl | DelimMinus),
+            DelimDotOrPlus => matches!(other, Number | Percentage | Dimension),
+            DelimAssorted | DelimAsterisk => matches!(other, DelimEquals),
+            DelimBar => matches!(other, DelimEquals | DelimBar | DashMatch),
+            DelimSlash => matches!(other, DelimAsterisk | SubstringMatch),
+            Nothing | WhiteSpace | Percentage | UrlOrBadUrl | Function | CDC | OpenParen
+            | DashMatch | SubstringMatch | DelimQuestion | DelimEquals | DelimPercent | Other => {
+                false
+            }
+        }
+    }
+}
+
+impl<'a> Token<'a> {
+    /// Categorize a token into a type that determines when `/**/` needs to be inserted
+    /// between two tokens when serialized next to each other without whitespace in between.
+    ///
+    /// See the `TokenSerializationType::needs_separator_when_before` method.
+    pub fn serialization_type(&self) -> TokenSerializationType {
+        use self::TokenSerializationType::*;
+        match self {
+            Token::Ident(_) => Ident,
+            Token::AtKeyword(_) | Token::Hash(_) | Token::IDHash(_) => AtKeywordOrHash,
+            Token::UnquotedUrl(_) | Token::BadUrl(_) => UrlOrBadUrl,
+            Token::Delim('#') => DelimHash,
+            Token::Delim('@') => DelimAt,
+            Token::Delim('.') | Token::Delim('+') => DelimDotOrPlus,
+            Token::Delim('-') => DelimMinus,
+            Token::Delim('?') => DelimQuestion,
+            Token::Delim('$') | Token::Delim('^') | Token::Delim('~') => DelimAssorted,
+            Token::Delim('%') => DelimPercent,
+            Token::Delim('=') => DelimEquals,
+            Token::Delim('|') => DelimBar,
+            Token::Delim('/') => DelimSlash,
+            Token::Delim('*') => DelimAsterisk,
+            Token::Number { .. } => Number,
+            Token::Percentage { .. } => Percentage,
+            Token::Dimension { .. } => Dimension,
+            Token::WhiteSpace(_) => WhiteSpace,
+            Token::Comment(_) => DelimSlash,
+            Token::DashMatch => DashMatch,
+            Token::SubstringMatch => SubstringMatch,
+            Token::CDC => CDC,
+            Token::Function(_) => Function,
+            Token::ParenthesisBlock => OpenParen,
+            Token::SquareBracketBlock
+            | Token::CurlyBracketBlock
+            | Token::CloseParenthesis
+            | Token::CloseSquareBracket
+            | Token::CloseCurlyBracket
+            | Token::QuotedString(_)
+            | Token::BadString(_)
+            | Token::Delim(_)
+            | Token::Colon
+            | Token::Semicolon
+            | Token::Comma
+            | Token::CDO
+            | Token::IncludeMatch
+            | Token::PrefixMatch
+            | Token::SuffixMatch => Other,
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/size_of_tests.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/size_of_tests.rs
new file mode 100644
index 000000000000..edd2b439f022
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/size_of_tests.rs
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::cow_rc_str::CowRcStr;
+use crate::tokenizer::Token;
+
+macro_rules! size_of_test {
+    ($testname: ident, $t: ty, $expected_min_size: expr, $expected_max_size: expr) => {
+        #[test]
+        fn $testname() {
+            let new = ::std::mem::size_of::<$t>();
+            if new < $expected_min_size {
+                panic!(
+                    "Your changes have decreased the stack size of {} from {} to {}. \
+                     Good work! Please update the expected size in {}.",
+                    stringify!($t),
+                    $expected_min_size,
+                    new,
+                    file!()
+                )
+            } else if new > $expected_max_size {
+                panic!(
+                    "Your changes have increased the stack size of {} from {} to {}. \
+                     Please consider choosing a design which avoids this increase. \
+                     If you feel that the increase is necessary, update the size in {}.",
+                    stringify!($t),
+                    $expected_max_size,
+                    new,
+                    file!()
+                )
+            }
+        }
+    };
+    ($testname: ident, $t: ty, $expected_size: expr) => {
+        size_of_test!($testname, $t, $expected_size, $expected_size);
+    };
+}
+
+// Some of these assume 64-bit
+size_of_test!(token, Token, 32);
+size_of_test!(std_cow_str, std::borrow::Cow<'static, str>, 24, 32);
+size_of_test!(cow_rc_str, CowRcStr, 16);
+
+size_of_test!(tokenizer, crate::tokenizer::Tokenizer, 72);
+size_of_test!(parser_input, crate::parser::ParserInput, 136);
+size_of_test!(parser, crate::parser::Parser, 16);
+size_of_test!(source_position, crate::SourcePosition, 8);
+size_of_test!(parser_state, crate::ParserState, 24);
+
+size_of_test!(basic_parse_error, crate::BasicParseError, 40, 48);
+size_of_test!(parse_error_lower_bound, crate::ParseError<()>, 40, 48);
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tests.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tests.rs
new file mode 100644
index 000000000000..7389664de409
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tests.rs
@@ -0,0 +1,1352 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[cfg(feature = "bench")]
+extern crate test;
+
+use serde_json::{json, Map, Value};
+
+#[cfg(feature = "bench")]
+use self::test::Bencher;
+
+use super::{
+    parse_important, parse_nth, parse_one_declaration, parse_one_rule, stylesheet_encoding,
+    AtRuleParser, BasicParseError, BasicParseErrorKind, CowRcStr, DeclarationParser, Delimiter,
+    EncodingSupport, ParseError, ParseErrorKind, Parser, ParserInput, ParserState,
+    QualifiedRuleParser, RuleBodyItemParser, RuleBodyParser, SourceLocation, StyleSheetParser,
+    ToCss, Token, TokenSerializationType, UnicodeRange,
+};
+
+macro_rules! JArray {
+    ($($e: expr,)*) => { JArray![ $( $e ),* ] };
+    ($($e: expr),*) => { Value::Array(vec!( $( $e.to_json() ),* )) }
+}
+
+fn almost_equals(a: &Value, b: &Value) -> bool {
+    let var_name = match (a, b) {
+        (Value::Number(a), Value::Number(b)) => {
+            let a = a.as_f64().unwrap();
+            let b = b.as_f64().unwrap();
+            (a - b).abs() <= a.abs() * 1e-6
+        }
+
+        (&Value::Bool(a), &Value::Bool(b)) => a == b,
+        (Value::String(a), Value::String(b)) => a == b,
+        (Value::Array(a), Value::Array(b)) => {
+            a.len() == b.len() && a.iter().zip(b.iter()).all(|(a, b)| almost_equals(a, b))
+        }
+        (&Value::Object(_), &Value::Object(_)) => panic!("Not implemented"),
+        (&Value::Null, &Value::Null) => true,
+        _ => false,
+    };
+    var_name
+}
+
+fn normalize(json: &mut Value) {
+    match *json {
+        Value::Array(ref mut list) => {
+            for item in list.iter_mut() {
+                normalize(item)
+            }
+        }
+        Value::String(ref mut s) => {
+            if *s == "extra-input" || *s == "empty" {
+                *s = "invalid".to_string()
+            }
+        }
+        _ => {}
+    }
+}
+
+fn assert_json_eq(results: Value, mut expected: Value, message: &str) {
+    normalize(&mut expected);
+    if !almost_equals(&results, &expected) {
+        println!(
+            "{}",
+            ::difference::Changeset::new(
+                &serde_json::to_string_pretty(&results).unwrap(),
+                &serde_json::to_string_pretty(&expected).unwrap(),
+                "\n",
+            )
+        );
+        panic!("{}", message)
+    }
+}
+
+fn run_raw_json_tests<F: Fn(Value, Value)>(json_data: &str, run: F) {
+    let items = match serde_json::from_str(json_data) {
+        Ok(Value::Array(items)) => items,
+        other => panic!("Invalid JSON: {:?}", other),
+    };
+    assert!(items.len() % 2 == 0);
+    let mut input = None;
+    for item in items.into_iter() {
+        match (&input, item) {
+            (&None, json_obj) => input = Some(json_obj),
+            (&Some(_), expected) => {
+                let input = input.take().unwrap();
+                run(input, expected)
+            }
+        };
+    }
+}
+
+fn run_json_tests<F: Fn(&mut Parser) -> Value>(json_data: &str, parse: F) {
+    run_raw_json_tests(json_data, |input, expected| match input {
+        Value::String(input) => {
+            let mut parse_input = ParserInput::new(&input);
+            let result = parse(&mut Parser::new(&mut parse_input));
+            assert_json_eq(result, expected, &input);
+        }
+        _ => panic!("Unexpected JSON"),
+    });
+}
+
+#[test]
+fn component_value_list() {
+    run_json_tests(
+        include_str!("css-parsing-tests/component_value_list.json"),
+        |input| Value::Array(component_values_to_json(input)),
+    );
+}
+
+#[test]
+fn one_component_value() {
+    run_json_tests(
+        include_str!("css-parsing-tests/one_component_value.json"),
+        |input| {
+            let result: Result<Value, ParseError<()>> = input.parse_entirely(|input| {
+                Ok(one_component_value_to_json(input.next()?.clone(), input))
+            });
+            result.unwrap_or(JArray!["error", "invalid"])
+        },
+    );
+}
+
+#[test]
+fn declaration_list() {
+    run_json_tests(
+        include_str!("css-parsing-tests/declaration_list.json"),
+        |input| {
+            Value::Array(
+                RuleBodyParser::new(input, &mut JsonParser)
+                    .map(|result| result.unwrap_or(JArray!["error", "invalid"]))
+                    .collect(),
+            )
+        },
+    );
+}
+
+#[test]
+fn one_declaration() {
+    run_json_tests(
+        include_str!("css-parsing-tests/one_declaration.json"),
+        |input| {
+            parse_one_declaration(input, &mut JsonParser).unwrap_or(JArray!["error", "invalid"])
+        },
+    );
+}
+
+#[test]
+fn rule_list() {
+    run_json_tests(include_str!("css-parsing-tests/rule_list.json"), |input| {
+        Value::Array(
+            RuleBodyParser::new(input, &mut JsonParser)
+                .map(|result| result.unwrap_or(JArray!["error", "invalid"]))
+                .collect(),
+        )
+    });
+}
+
+#[test]
+fn stylesheet() {
+    run_json_tests(include_str!("css-parsing-tests/stylesheet.json"), |input| {
+        Value::Array(
+            StyleSheetParser::new(input, &mut JsonParser)
+                .map(|result| result.unwrap_or(JArray!["error", "invalid"]))
+                .collect(),
+        )
+    });
+}
+
+#[test]
+fn one_rule() {
+    run_json_tests(include_str!("css-parsing-tests/one_rule.json"), |input| {
+        parse_one_rule(input, &mut JsonParser).unwrap_or(JArray!["error", "invalid"])
+    });
+}
+
+#[test]
+fn stylesheet_from_bytes() {
+    pub struct EncodingRs;
+
+    impl EncodingSupport for EncodingRs {
+        type Encoding = &'static encoding_rs::Encoding;
+
+        fn utf8() -> Self::Encoding {
+            encoding_rs::UTF_8
+        }
+
+        fn is_utf16_be_or_le(encoding: &Self::Encoding) -> bool {
+            *encoding == encoding_rs::UTF_16LE || *encoding == encoding_rs::UTF_16BE
+        }
+
+        fn from_label(ascii_label: &[u8]) -> Option<Self::Encoding> {
+            encoding_rs::Encoding::for_label(ascii_label)
+        }
+    }
+
+    run_raw_json_tests(
+        include_str!("css-parsing-tests/stylesheet_bytes.json"),
+        |input, expected| {
+            let map = match input {
+                Value::Object(map) => map,
+                _ => panic!("Unexpected JSON"),
+            };
+
+            let result = {
+                let css = get_string(&map, "css_bytes")
+                    .unwrap()
+                    .chars()
+                    .map(|c| {
+                        assert!(c as u32 <= 0xFF);
+                        c as u8
+                    })
+                    .collect::<Vec<u8>>();
+                let protocol_encoding_label =
+                    get_string(&map, "protocol_encoding").map(|s| s.as_bytes());
+                let environment_encoding = get_string(&map, "environment_encoding")
+                    .map(|s| s.as_bytes())
+                    .and_then(EncodingRs::from_label);
+
+                let encoding = stylesheet_encoding::<EncodingRs>(
+                    &css,
+                    protocol_encoding_label,
+                    environment_encoding,
+                );
+                let (css_unicode, used_encoding, _) = encoding.decode(&css);
+                let mut input = ParserInput::new(&css_unicode);
+                let input = &mut Parser::new(&mut input);
+                let rules = StyleSheetParser::new(input, &mut JsonParser)
+                    .map(|result| result.unwrap_or(JArray!["error", "invalid"]))
+                    .collect::<Vec<_>>();
+                JArray![rules, used_encoding.name().to_lowercase()]
+            };
+            assert_json_eq(result, expected, &Value::Object(map).to_string());
+        },
+    );
+
+    fn get_string<'a>(map: &'a Map<String, Value>, key: &str) -> Option<&'a str> {
+        match map.get(key) {
+            Some(Value::String(s)) => Some(s),
+            Some(&Value::Null) => None,
+            None => None,
+            _ => panic!("Unexpected JSON"),
+        }
+    }
+}
+
+#[test]
+fn expect_no_error_token() {
+    let mut input = ParserInput::new("foo 4px ( / { !bar }");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_ok());
+    let mut input = ParserInput::new(")");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("}");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("(a){]");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("'\n'");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("url('\n'");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("url(a b)");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+    let mut input = ParserInput::new("url(\u{7F}))");
+    assert!(Parser::new(&mut input).expect_no_error_token().is_err());
+}
+
+/// https://github.com/servo/rust-cssparser/issues/71
+#[test]
+fn outer_block_end_consumed() {
+    let mut input = ParserInput::new("(calc(true))");
+    let mut input = Parser::new(&mut input);
+    assert!(input.expect_parenthesis_block().is_ok());
+    assert!(input
+        .parse_nested_block(|input| input
+            .expect_function_matching("calc")
+            .map_err(Into::<ParseError<()>>::into))
+        .is_ok());
+    println!("{:?}", input.position());
+    assert!(input.next().is_err());
+}
+
+/// https://github.com/servo/rust-cssparser/issues/174
+#[test]
+fn bad_url_slice_out_of_bounds() {
+    let mut input = ParserInput::new("url(\u{1}\\");
+    let mut parser = Parser::new(&mut input);
+    let result = parser.next_including_whitespace_and_comments(); // This used to panic
+    assert_eq!(result, Ok(&Token::BadUrl("\u{1}\\".into())));
+}
+
+/// https://bugzilla.mozilla.org/show_bug.cgi?id=1383975
+#[test]
+fn bad_url_slice_not_at_char_boundary() {
+    let mut input = ParserInput::new("url(9\n۰");
+    let mut parser = Parser::new(&mut input);
+    let result = parser.next_including_whitespace_and_comments(); // This used to panic
+    assert_eq!(result, Ok(&Token::BadUrl("9\n۰".into())));
+}
+
+#[test]
+fn unquoted_url_escaping() {
+    let token = Token::UnquotedUrl(
+        "\
+         \x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\
+         \x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f \
+         !\"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]\
+         ^_`abcdefghijklmnopqrstuvwxyz{|}~\x7fé\
+         "
+        .into(),
+    );
+    let serialized = token.to_css_string();
+    assert_eq!(
+        serialized,
+        "\
+         url(\
+         \\1 \\2 \\3 \\4 \\5 \\6 \\7 \\8 \\9 \\a \\b \\c \\d \\e \\f \\10 \
+         \\11 \\12 \\13 \\14 \\15 \\16 \\17 \\18 \\19 \\1a \\1b \\1c \\1d \\1e \\1f \\20 \
+         !\\\"#$%&\\'\\(\\)*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]\
+         ^_`abcdefghijklmnopqrstuvwxyz{|}~\\7f é\
+         )\
+         "
+    );
+    let mut input = ParserInput::new(&serialized);
+    assert_eq!(Parser::new(&mut input).next(), Ok(&token));
+}
+
+#[test]
+fn test_expect_url() {
+    fn parse<'a>(s: &mut ParserInput<'a>) -> Result<CowRcStr<'a>, BasicParseError<'a>> {
+        Parser::new(s).expect_url()
+    }
+    let mut input = ParserInput::new("url()");
+    assert_eq!(parse(&mut input).unwrap(), "");
+    let mut input = ParserInput::new("url( ");
+    assert_eq!(parse(&mut input).unwrap(), "");
+    let mut input = ParserInput::new("url( abc");
+    assert_eq!(parse(&mut input).unwrap(), "abc");
+    let mut input = ParserInput::new("url( abc \t)");
+    assert_eq!(parse(&mut input).unwrap(), "abc");
+    let mut input = ParserInput::new("url( 'abc' \t)");
+    assert_eq!(parse(&mut input).unwrap(), "abc");
+    let mut input = ParserInput::new("url(abc more stuff)");
+    assert!(parse(&mut input).is_err());
+    // The grammar at https://drafts.csswg.org/css-values/#urls plans for `<url-modifier>*`
+    // at the position of "more stuff", but no such modifier is defined yet.
+    let mut input = ParserInput::new("url('abc' more stuff)");
+    assert!(parse(&mut input).is_err());
+}
+
+#[test]
+fn nth() {
+    run_json_tests(include_str!("css-parsing-tests/An+B.json"), |input| {
+        input
+            .parse_entirely(|i| {
+                let result: Result<_, ParseError<()>> = parse_nth(i).map_err(Into::into);
+                result
+            })
+            .ok()
+            .map(|(v0, v1)| json!([v0, v1]))
+            .unwrap_or(Value::Null)
+    });
+}
+
+#[test]
+fn parse_comma_separated_ignoring_errors() {
+    let input = "red, green something, yellow, whatever, blue";
+    let mut input = ParserInput::new(input);
+    let mut input = Parser::new(&mut input);
+    let result = input.parse_comma_separated_ignoring_errors(|input| {
+        let loc = input.current_source_location();
+        let ident = input.expect_ident()?;
+        crate::color::parse_named_color(ident).map_err(|()| {
+            loc.new_unexpected_token_error::<ParseError<()>>(Token::Ident(ident.clone()))
+        })
+    });
+    assert_eq!(result.len(), 3);
+    assert_eq!(result[0], (255, 0, 0));
+    assert_eq!(result[1], (255, 255, 0));
+    assert_eq!(result[2], (0, 0, 255));
+}
+
+#[test]
+fn unicode_range() {
+    run_json_tests(include_str!("css-parsing-tests/urange.json"), |input| {
+        let result: Result<_, ParseError<()>> = input.parse_comma_separated(|input| {
+            let result = UnicodeRange::parse(input).ok().map(|r| (r.start, r.end));
+            if input.is_exhausted() {
+                Ok(result)
+            } else {
+                while input.next().is_ok() {}
+                Ok(None)
+            }
+        });
+        result
+            .unwrap()
+            .iter()
+            .map(|v| {
+                if let Some((v0, v1)) = v {
+                    json!([v0, v1])
+                } else {
+                    Value::Null
+                }
+            })
+            .collect::<Vec<_>>()
+            .to_json()
+    });
+}
+
+#[test]
+fn serializer_not_preserving_comments() {
+    serializer(false)
+}
+
+#[test]
+fn serializer_preserving_comments() {
+    serializer(true)
+}
+
+fn serializer(preserve_comments: bool) {
+    run_json_tests(
+        include_str!("css-parsing-tests/component_value_list.json"),
+        |input| {
+            fn write_to(
+                mut previous_token: TokenSerializationType,
+                input: &mut Parser,
+                string: &mut String,
+                preserve_comments: bool,
+            ) {
+                while let Ok(token) = if preserve_comments {
+                    input.next_including_whitespace_and_comments().cloned()
+                } else {
+                    input.next_including_whitespace().cloned()
+                } {
+                    let token_type = token.serialization_type();
+                    if !preserve_comments && previous_token.needs_separator_when_before(token_type)
+                    {
+                        string.push_str("/**/")
+                    }
+                    previous_token = token_type;
+                    token.to_css(string).unwrap();
+                    let closing_token = match token {
+                        Token::Function(_) | Token::ParenthesisBlock => {
+                            Some(Token::CloseParenthesis)
+                        }
+                        Token::SquareBracketBlock => Some(Token::CloseSquareBracket),
+                        Token::CurlyBracketBlock => Some(Token::CloseCurlyBracket),
+                        _ => None,
+                    };
+                    if let Some(closing_token) = closing_token {
+                        let result: Result<_, ParseError<()>> = input.parse_nested_block(|input| {
+                            write_to(previous_token, input, string, preserve_comments);
+                            Ok(())
+                        });
+                        result.unwrap();
+                        closing_token.to_css(string).unwrap();
+                    }
+                }
+            }
+            let mut serialized = String::new();
+            write_to(
+                TokenSerializationType::Nothing,
+                input,
+                &mut serialized,
+                preserve_comments,
+            );
+            let mut input = ParserInput::new(&serialized);
+            let parser = &mut Parser::new(&mut input);
+            Value::Array(component_values_to_json(parser))
+        },
+    );
+}
+
+#[test]
+fn serialize_bad_tokens() {
+    let mut input = ParserInput::new("url(foo\\) b\\)ar)'ba\\'\"z\n4");
+    let mut parser = Parser::new(&mut input);
+
+    let token = parser.next().unwrap().clone();
+    assert!(matches!(token, Token::BadUrl(_)));
+    assert_eq!(token.to_css_string(), "url(foo\\) b\\)ar)");
+
+    let token = parser.next().unwrap().clone();
+    assert!(matches!(token, Token::BadString(_)));
+    assert_eq!(token.to_css_string(), "\"ba'\\\"z");
+
+    let token = parser.next().unwrap().clone();
+    assert!(matches!(token, Token::Number { .. }));
+    assert_eq!(token.to_css_string(), "4");
+
+    assert!(parser.next().is_err());
+}
+
+#[test]
+fn line_numbers() {
+    let mut input = ParserInput::new(concat!(
+        "fo\\30\r\n",
+        "0o bar/*\n",
+        "*/baz\r\n",
+        "\n",
+        "url(\r\n",
+        "  u \r\n",
+        ")\"a\\\r\n",
+        "b\""
+    ));
+    let mut input = Parser::new(&mut input);
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 0, column: 1 }
+    );
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::Ident("fo00o".into()))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 1, column: 3 }
+    );
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::WhiteSpace(" "))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 1, column: 4 }
+    );
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::Ident("bar".into()))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 1, column: 7 }
+    );
+    assert_eq!(
+        input.next_including_whitespace_and_comments(),
+        Ok(&Token::Comment("\n"))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 2, column: 3 }
+    );
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::Ident("baz".into()))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 2, column: 6 }
+    );
+    let state = input.state();
+
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::WhiteSpace("\r\n\n"))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 4, column: 1 }
+    );
+
+    assert_eq!(
+        state.source_location(),
+        SourceLocation { line: 2, column: 6 }
+    );
+
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::UnquotedUrl("u".into()))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 6, column: 2 }
+    );
+
+    assert_eq!(
+        input.next_including_whitespace(),
+        Ok(&Token::QuotedString("ab".into()))
+    );
+    assert_eq!(
+        input.current_source_location(),
+        SourceLocation { line: 7, column: 3 }
+    );
+    assert!(input.next_including_whitespace().is_err());
+}
+
+#[test]
+fn overflow() {
+    let css = r"
+         2147483646
+         2147483647
+         2147483648
+         10000000000000
+         1000000000000000000000000000000000000000
+         1{309 zeros}
+
+         -2147483647
+         -2147483648
+         -2147483649
+         -10000000000000
+         -1000000000000000000000000000000000000000
+         -1{309 zeros}
+
+         3.30282347e+38
+         3.40282347e+38
+         3.402824e+38
+
+         -3.30282347e+38
+         -3.40282347e+38
+         -3.402824e+38
+
+    "
+    .replace("{309 zeros}", &"0".repeat(309));
+    let mut input = ParserInput::new(&css);
+    let mut input = Parser::new(&mut input);
+
+    assert_eq!(input.expect_integer(), Ok(2147483646));
+    assert_eq!(input.expect_integer(), Ok(2147483647));
+    assert_eq!(input.expect_integer(), Ok(2147483647)); // Clamp on overflow
+    assert_eq!(input.expect_integer(), Ok(2147483647));
+    assert_eq!(input.expect_integer(), Ok(2147483647));
+    assert_eq!(input.expect_integer(), Ok(2147483647));
+
+    assert_eq!(input.expect_integer(), Ok(-2147483647));
+    assert_eq!(input.expect_integer(), Ok(-2147483648));
+    assert_eq!(input.expect_integer(), Ok(-2147483648)); // Clamp on overflow
+    assert_eq!(input.expect_integer(), Ok(-2147483648));
+    assert_eq!(input.expect_integer(), Ok(-2147483648));
+    assert_eq!(input.expect_integer(), Ok(-2147483648));
+
+    assert_eq!(input.expect_number(), Ok(3.302_823_5e38));
+    assert_eq!(input.expect_number(), Ok(f32::MAX));
+    assert_eq!(input.expect_number(), Ok(f32::INFINITY));
+
+    assert_eq!(input.expect_number(), Ok(-3.302_823_5e38));
+    assert_eq!(input.expect_number(), Ok(f32::MIN));
+    assert_eq!(input.expect_number(), Ok(f32::NEG_INFINITY));
+}
+
+#[test]
+fn line_delimited() {
+    let mut input = ParserInput::new(" { foo ; bar } baz;,");
+    let mut input = Parser::new(&mut input);
+    assert_eq!(input.next(), Ok(&Token::CurlyBracketBlock));
+    assert!({
+        let result: Result<_, ParseError<()>> =
+            input.parse_until_after(Delimiter::Semicolon, |_| Ok(42));
+        result
+    }
+    .is_err());
+    assert_eq!(input.next(), Ok(&Token::Comma));
+    assert!(input.next().is_err());
+}
+
+#[test]
+fn identifier_serialization() {
+    // Null bytes
+    assert_eq!(Token::Ident("\0".into()).to_css_string(), "\u{FFFD}");
+    assert_eq!(Token::Ident("a\0".into()).to_css_string(), "a\u{FFFD}");
+    assert_eq!(Token::Ident("\0b".into()).to_css_string(), "\u{FFFD}b");
+    assert_eq!(Token::Ident("a\0b".into()).to_css_string(), "a\u{FFFD}b");
+
+    // Replacement character
+    assert_eq!(Token::Ident("\u{FFFD}".into()).to_css_string(), "\u{FFFD}");
+    assert_eq!(
+        Token::Ident("a\u{FFFD}".into()).to_css_string(),
+        "a\u{FFFD}"
+    );
+    assert_eq!(
+        Token::Ident("\u{FFFD}b".into()).to_css_string(),
+        "\u{FFFD}b"
+    );
+    assert_eq!(
+        Token::Ident("a\u{FFFD}b".into()).to_css_string(),
+        "a\u{FFFD}b"
+    );
+
+    // Number prefix
+    assert_eq!(Token::Ident("0a".into()).to_css_string(), "\\30 a");
+    assert_eq!(Token::Ident("1a".into()).to_css_string(), "\\31 a");
+    assert_eq!(Token::Ident("2a".into()).to_css_string(), "\\32 a");
+    assert_eq!(Token::Ident("3a".into()).to_css_string(), "\\33 a");
+    assert_eq!(Token::Ident("4a".into()).to_css_string(), "\\34 a");
+    assert_eq!(Token::Ident("5a".into()).to_css_string(), "\\35 a");
+    assert_eq!(Token::Ident("6a".into()).to_css_string(), "\\36 a");
+    assert_eq!(Token::Ident("7a".into()).to_css_string(), "\\37 a");
+    assert_eq!(Token::Ident("8a".into()).to_css_string(), "\\38 a");
+    assert_eq!(Token::Ident("9a".into()).to_css_string(), "\\39 a");
+
+    // Letter number prefix
+    assert_eq!(Token::Ident("a0b".into()).to_css_string(), "a0b");
+    assert_eq!(Token::Ident("a1b".into()).to_css_string(), "a1b");
+    assert_eq!(Token::Ident("a2b".into()).to_css_string(), "a2b");
+    assert_eq!(Token::Ident("a3b".into()).to_css_string(), "a3b");
+    assert_eq!(Token::Ident("a4b".into()).to_css_string(), "a4b");
+    assert_eq!(Token::Ident("a5b".into()).to_css_string(), "a5b");
+    assert_eq!(Token::Ident("a6b".into()).to_css_string(), "a6b");
+    assert_eq!(Token::Ident("a7b".into()).to_css_string(), "a7b");
+    assert_eq!(Token::Ident("a8b".into()).to_css_string(), "a8b");
+    assert_eq!(Token::Ident("a9b".into()).to_css_string(), "a9b");
+
+    // Dash number prefix
+    assert_eq!(Token::Ident("-0a".into()).to_css_string(), "-\\30 a");
+    assert_eq!(Token::Ident("-1a".into()).to_css_string(), "-\\31 a");
+    assert_eq!(Token::Ident("-2a".into()).to_css_string(), "-\\32 a");
+    assert_eq!(Token::Ident("-3a".into()).to_css_string(), "-\\33 a");
+    assert_eq!(Token::Ident("-4a".into()).to_css_string(), "-\\34 a");
+    assert_eq!(Token::Ident("-5a".into()).to_css_string(), "-\\35 a");
+    assert_eq!(Token::Ident("-6a".into()).to_css_string(), "-\\36 a");
+    assert_eq!(Token::Ident("-7a".into()).to_css_string(), "-\\37 a");
+    assert_eq!(Token::Ident("-8a".into()).to_css_string(), "-\\38 a");
+    assert_eq!(Token::Ident("-9a".into()).to_css_string(), "-\\39 a");
+
+    // Double dash prefix
+    assert_eq!(Token::Ident("--a".into()).to_css_string(), "--a");
+
+    // Various tests
+    assert_eq!(
+        Token::Ident("\x01\x02\x1E\x1F".into()).to_css_string(),
+        "\\1 \\2 \\1e \\1f "
+    );
+    assert_eq!(
+        Token::Ident("\u{0080}\x2D\x5F\u{00A9}".into()).to_css_string(),
+        "\u{0080}\x2D\x5F\u{00A9}"
+    );
+    assert_eq!(Token::Ident("\x7F\u{0080}\u{0081}\u{0082}\u{0083}\u{0084}\u{0085}\u{0086}\u{0087}\u{0088}\u{0089}\
+        \u{008A}\u{008B}\u{008C}\u{008D}\u{008E}\u{008F}\u{0090}\u{0091}\u{0092}\u{0093}\u{0094}\u{0095}\u{0096}\
+        \u{0097}\u{0098}\u{0099}\u{009A}\u{009B}\u{009C}\u{009D}\u{009E}\u{009F}".into()).to_css_string(),
+        "\\7f \u{0080}\u{0081}\u{0082}\u{0083}\u{0084}\u{0085}\u{0086}\u{0087}\u{0088}\u{0089}\u{008A}\u{008B}\u{008C}\
+        \u{008D}\u{008E}\u{008F}\u{0090}\u{0091}\u{0092}\u{0093}\u{0094}\u{0095}\u{0096}\u{0097}\u{0098}\u{0099}\
+        \u{009A}\u{009B}\u{009C}\u{009D}\u{009E}\u{009F}");
+    assert_eq!(
+        Token::Ident("\u{00A0}\u{00A1}\u{00A2}".into()).to_css_string(),
+        "\u{00A0}\u{00A1}\u{00A2}"
+    );
+    assert_eq!(
+        Token::Ident("a0123456789b".into()).to_css_string(),
+        "a0123456789b"
+    );
+    assert_eq!(
+        Token::Ident("abcdefghijklmnopqrstuvwxyz".into()).to_css_string(),
+        "abcdefghijklmnopqrstuvwxyz"
+    );
+    assert_eq!(
+        Token::Ident("ABCDEFGHIJKLMNOPQRSTUVWXYZ".into()).to_css_string(),
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    );
+    assert_eq!(
+        Token::Ident("\x20\x21\x78\x79".into()).to_css_string(),
+        "\\ \\!xy"
+    );
+
+    // astral symbol (U+1D306 TETRAGRAM FOR CENTRE)
+    assert_eq!(
+        Token::Ident("\u{1D306}".into()).to_css_string(),
+        "\u{1D306}"
+    );
+}
+
+trait ToJson {
+    fn to_json(&self) -> Value;
+}
+
+impl<T> ToJson for T
+where
+    T: Clone,
+    Value: From<T>,
+{
+    fn to_json(&self) -> Value {
+        Value::from(self.clone())
+    }
+}
+
+impl<'a> ToJson for CowRcStr<'a> {
+    fn to_json(&self) -> Value {
+        let s: &str = self;
+        s.to_json()
+    }
+}
+
+#[bench]
+#[cfg(feature = "bench")]
+fn delimiter_from_byte(b: &mut Bencher) {
+    use crate::Delimiters;
+    b.iter(|| {
+        for _ in 0..1000 {
+            for i in 0..256 {
+                std::hint::black_box(Delimiters::from_byte(Some(i as u8)));
+            }
+        }
+    })
+}
+
+#[cfg(feature = "bench")]
+const BACKGROUND_IMAGE: &'static str = include_str!("big-data-url.css");
+
+#[cfg(feature = "bench")]
+#[bench]
+fn unquoted_url(b: &mut Bencher) {
+    b.iter(|| {
+        let mut input = ParserInput::new(BACKGROUND_IMAGE);
+        let mut input = Parser::new(&mut input);
+        input.look_for_var_or_env_functions();
+
+        let result = input.try_parse(|input| input.expect_url());
+
+        assert!(result.is_ok());
+
+        input.seen_var_or_env_functions();
+        (result.is_ok(), input.seen_var_or_env_functions())
+    })
+}
+
+#[cfg_attr(all(miri, feature = "skip_long_tests"), ignore)]
+#[cfg(feature = "bench")]
+#[bench]
+fn numeric(b: &mut Bencher) {
+    b.iter(|| {
+        for _ in 0..1000000 {
+            let mut input = ParserInput::new("10px");
+            let mut input = Parser::new(&mut input);
+            let _ = test::black_box(input.next());
+        }
+    })
+}
+
+struct JsonParser;
+
+#[cfg_attr(all(miri, feature = "skip_long_tests"), ignore)]
+#[test]
+fn no_stack_overflow_multiple_nested_blocks() {
+    let mut input: String = "{{".into();
+    for _ in 0..20 {
+        let dup = input.clone();
+        input.push_str(&dup);
+    }
+    let mut input = ParserInput::new(&input);
+    let mut input = Parser::new(&mut input);
+    while input.next().is_ok() {}
+}
+
+impl<'i> DeclarationParser<'i> for JsonParser {
+    type Declaration = Value;
+    type Error = ();
+
+    fn parse_value<'t>(
+        &mut self,
+        name: CowRcStr<'i>,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Value, ParseError<'i, ()>> {
+        let mut value = vec![];
+        let mut important = false;
+        loop {
+            let start = input.state();
+            if let Ok(mut token) = input.next_including_whitespace().cloned() {
+                // Hack to deal with css-parsing-tests assuming that
+                // `!important` in the middle of a declaration value is OK.
+                // This can never happen per spec
+                // (even CSS Variables forbid top-level `!`)
+                if token == Token::Delim('!') {
+                    input.reset(&start);
+                    if parse_important(input).is_ok() && input.is_exhausted() {
+                        important = true;
+                        break;
+                    }
+                    input.reset(&start);
+                    token = input.next_including_whitespace().unwrap().clone();
+                }
+                value.push(one_component_value_to_json(token, input));
+            } else {
+                break;
+            }
+        }
+        Ok(JArray!["declaration", name, value, important,])
+    }
+}
+
+impl<'i> AtRuleParser<'i> for JsonParser {
+    type Prelude = Vec<Value>;
+    type AtRule = Value;
+    type Error = ();
+
+    fn parse_prelude<'t>(
+        &mut self,
+        name: CowRcStr<'i>,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Vec<Value>, ParseError<'i, ()>> {
+        let prelude = vec![
+            "at-rule".to_json(),
+            name.to_json(),
+            Value::Array(component_values_to_json(input)),
+        ];
+        match_ignore_ascii_case! { &*name,
+            "charset" => {
+                Err(input.new_error(BasicParseErrorKind::AtRuleInvalid(name.clone())))
+            },
+            _ => Ok(prelude),
+        }
+    }
+
+    fn rule_without_block(
+        &mut self,
+        mut prelude: Vec<Value>,
+        _: &ParserState,
+    ) -> Result<Value, ()> {
+        prelude.push(Value::Null);
+        Ok(Value::Array(prelude))
+    }
+
+    fn parse_block<'t>(
+        &mut self,
+        mut prelude: Vec<Value>,
+        _: &ParserState,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Value, ParseError<'i, ()>> {
+        prelude.push(Value::Array(component_values_to_json(input)));
+        Ok(Value::Array(prelude))
+    }
+}
+
+impl<'i> QualifiedRuleParser<'i> for JsonParser {
+    type Prelude = Vec<Value>;
+    type QualifiedRule = Value;
+    type Error = ();
+
+    fn parse_prelude<'t>(
+        &mut self,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Vec<Value>, ParseError<'i, ()>> {
+        Ok(component_values_to_json(input))
+    }
+
+    fn parse_block<'t>(
+        &mut self,
+        prelude: Vec<Value>,
+        _: &ParserState,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Value, ParseError<'i, ()>> {
+        Ok(JArray![
+            "qualified rule",
+            prelude,
+            component_values_to_json(input),
+        ])
+    }
+}
+
+impl<'i> RuleBodyItemParser<'i, Value, ()> for JsonParser {
+    fn parse_qualified(&self) -> bool {
+        true
+    }
+    fn parse_declarations(&self) -> bool {
+        true
+    }
+}
+
+fn component_values_to_json(input: &mut Parser) -> Vec<Value> {
+    let mut values = vec![];
+    while let Ok(token) = input.next_including_whitespace().cloned() {
+        values.push(one_component_value_to_json(token, input));
+    }
+    values
+}
+
+fn one_component_value_to_json(token: Token, input: &mut Parser) -> Value {
+    fn numeric(value: f32, int_value: Option<i32>, has_sign: bool) -> Vec<Value> {
+        vec![
+            Token::Number {
+                value,
+                int_value,
+                has_sign,
+            }
+            .to_css_string()
+            .to_json(),
+            match int_value {
+                Some(i) => i.to_json(),
+                None => value.to_json(),
+            },
+            match int_value {
+                Some(_) => "integer",
+                None => "number",
+            }
+            .to_json(),
+        ]
+    }
+
+    fn nested(input: &mut Parser) -> Vec<Value> {
+        let result: Result<_, ParseError<()>> =
+            input.parse_nested_block(|input| Ok(component_values_to_json(input)));
+        result.unwrap()
+    }
+
+    match token {
+        Token::Ident(value) => JArray!["ident", value],
+        Token::AtKeyword(value) => JArray!["at-keyword", value],
+        Token::Hash(value) => JArray!["hash", value, "unrestricted"],
+        Token::IDHash(value) => JArray!["hash", value, "id"],
+        Token::QuotedString(value) => JArray!["string", value],
+        Token::UnquotedUrl(value) => JArray!["url", value],
+        Token::Delim('\\') => "\\".to_json(),
+        Token::Delim(value) => value.to_string().to_json(),
+
+        Token::Number {
+            value,
+            int_value,
+            has_sign,
+        } => Value::Array({
+            let mut v = vec!["number".to_json()];
+            v.extend(numeric(value, int_value, has_sign));
+            v
+        }),
+        Token::Percentage {
+            unit_value,
+            int_value,
+            has_sign,
+        } => Value::Array({
+            let mut v = vec!["percentage".to_json()];
+            v.extend(numeric(unit_value * 100., int_value, has_sign));
+            v
+        }),
+        Token::Dimension {
+            value,
+            int_value,
+            has_sign,
+            unit,
+        } => Value::Array({
+            let mut v = vec!["dimension".to_json()];
+            v.extend(numeric(value, int_value, has_sign));
+            v.push(unit.to_json());
+            v
+        }),
+
+        Token::WhiteSpace(_) => " ".to_json(),
+        Token::Comment(_) => "/**/".to_json(),
+        Token::Colon => ":".to_json(),
+        Token::Semicolon => ";".to_json(),
+        Token::Comma => ",".to_json(),
+        Token::IncludeMatch => "~=".to_json(),
+        Token::DashMatch => "|=".to_json(),
+        Token::PrefixMatch => "^=".to_json(),
+        Token::SuffixMatch => "$=".to_json(),
+        Token::SubstringMatch => "*=".to_json(),
+        Token::CDO => "<!--".to_json(),
+        Token::CDC => "-->".to_json(),
+
+        Token::Function(name) => Value::Array({
+            let mut v = vec!["function".to_json(), name.to_json()];
+            v.extend(nested(input));
+            v
+        }),
+        Token::ParenthesisBlock => Value::Array({
+            let mut v = vec!["()".to_json()];
+            v.extend(nested(input));
+            v
+        }),
+        Token::SquareBracketBlock => Value::Array({
+            let mut v = vec!["[]".to_json()];
+            v.extend(nested(input));
+            v
+        }),
+        Token::CurlyBracketBlock => Value::Array({
+            let mut v = vec!["{}".to_json()];
+            v.extend(nested(input));
+            v
+        }),
+        Token::BadUrl(_) => JArray!["error", "bad-url"],
+        Token::BadString(_) => JArray!["error", "bad-string"],
+        Token::CloseParenthesis => JArray!["error", ")"],
+        Token::CloseSquareBracket => JArray!["error", "]"],
+        Token::CloseCurlyBracket => JArray!["error", "}"],
+    }
+}
+
+/// A previous version of procedural-masquerade had a bug where it
+/// would normalize consecutive whitespace to a single space,
+/// including in string literals.
+#[test]
+fn procedural_masquerade_whitespace() {
+    ascii_case_insensitive_phf_map! {
+        map -> () = {
+            "  \t\n" => ()
+        }
+    }
+    assert_eq!(map::get("  \t\n"), Some(&()));
+    assert_eq!(map::get(" "), None);
+
+    match_ignore_ascii_case! { "  \t\n",
+        " " => panic!("1"),
+        "  \t\n" => {},
+        _ => panic!("2"),
+    }
+
+    match_ignore_ascii_case! { " ",
+        "  \t\n" => panic!("3"),
+        " " => {},
+        _ => panic!("4"),
+    }
+}
+
+#[test]
+fn parse_until_before_stops_at_delimiter_or_end_of_input() {
+    // For all j and k, inputs[i].1[j] should parse the same as inputs[i].1[k]
+    // when we use delimiters inputs[i].0.
+    let inputs = vec![
+        (
+            Delimiter::Bang | Delimiter::Semicolon,
+            // Note that the ';extra' is fine, because the ';' acts the same as
+            // the end of input.
+            vec!["token stream;extra", "token stream!", "token stream"],
+        ),
+        (Delimiter::Bang | Delimiter::Semicolon, vec![";", "!", ""]),
+    ];
+    for equivalent in inputs {
+        for (j, x) in equivalent.1.iter().enumerate() {
+            for y in equivalent.1[j + 1..].iter() {
+                let mut ix = ParserInput::new(x);
+                let mut ix = Parser::new(&mut ix);
+
+                let mut iy = ParserInput::new(y);
+                let mut iy = Parser::new(&mut iy);
+
+                let _ = ix.parse_until_before::<_, _, ()>(equivalent.0, |ix| {
+                    iy.parse_until_before::<_, _, ()>(equivalent.0, |iy| {
+                        loop {
+                            let ox = ix.next();
+                            let oy = iy.next();
+                            assert_eq!(ox, oy);
+                            if ox.is_err() {
+                                break;
+                            }
+                        }
+                        Ok(())
+                    })
+                });
+            }
+        }
+    }
+}
+
+#[test]
+fn parser_maintains_current_line() {
+    let mut input = ParserInput::new("ident ident;\nident ident ident;\nident");
+    let mut parser = Parser::new(&mut input);
+    assert_eq!(parser.current_line(), "ident ident;");
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.next(), Ok(&Token::Semicolon));
+
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.current_line(), "ident ident ident;");
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.next(), Ok(&Token::Semicolon));
+
+    assert_eq!(parser.next(), Ok(&Token::Ident("ident".into())));
+    assert_eq!(parser.current_line(), "ident");
+}
+
+#[test]
+fn cdc_regression_test() {
+    let mut input = ParserInput::new("-->x");
+    let mut parser = Parser::new(&mut input);
+    parser.skip_cdc_and_cdo();
+    assert_eq!(parser.next(), Ok(&Token::Ident("x".into())));
+    assert_eq!(
+        parser.next(),
+        Err(BasicParseError {
+            kind: BasicParseErrorKind::EndOfInput,
+            location: SourceLocation { line: 0, column: 5 }
+        })
+    );
+}
+
+#[test]
+fn parse_entirely_reports_first_error() {
+    #[derive(PartialEq, Debug)]
+    enum E {
+        Foo,
+    }
+    let mut input = ParserInput::new("ident");
+    let mut parser = Parser::new(&mut input);
+    let result: Result<(), _> = parser.parse_entirely(|p| Err(p.new_custom_error(E::Foo)));
+    assert_eq!(
+        result,
+        Err(ParseError {
+            kind: ParseErrorKind::Custom(E::Foo),
+            location: SourceLocation { line: 0, column: 1 },
+        })
+    );
+}
+
+#[test]
+fn parse_sourcemapping_comments() {
+    let tests = vec![
+        ("/*# sourceMappingURL=here*/", Some("here")),
+        ("/*# sourceMappingURL=here  */", Some("here")),
+        ("/*@ sourceMappingURL=here*/", Some("here")),
+        (
+            "/*@ sourceMappingURL=there*/ /*# sourceMappingURL=here*/",
+            Some("here"),
+        ),
+        ("/*# sourceMappingURL=here there  */", Some("here")),
+        ("/*# sourceMappingURL=  here  */", Some("")),
+        ("/*# sourceMappingURL=*/", Some("")),
+        ("/*# sourceMappingUR=here  */", None),
+        ("/*! sourceMappingURL=here  */", None),
+        ("/*# sourceMappingURL = here  */", None),
+        ("/*   # sourceMappingURL=here   */", None),
+    ];
+
+    for test in tests {
+        let mut input = ParserInput::new(test.0);
+        let mut parser = Parser::new(&mut input);
+        while parser.next_including_whitespace().is_ok() {}
+        assert_eq!(parser.current_source_map_url(), test.1);
+    }
+}
+
+#[test]
+fn parse_sourceurl_comments() {
+    let tests = vec![
+        ("/*# sourceURL=here*/", Some("here")),
+        ("/*# sourceURL=here  */", Some("here")),
+        ("/*@ sourceURL=here*/", Some("here")),
+        ("/*@ sourceURL=there*/ /*# sourceURL=here*/", Some("here")),
+        ("/*# sourceURL=here there  */", Some("here")),
+        ("/*# sourceURL=  here  */", Some("")),
+        ("/*# sourceURL=*/", Some("")),
+        ("/*# sourceMappingUR=here  */", None),
+        ("/*! sourceURL=here  */", None),
+        ("/*# sourceURL = here  */", None),
+        ("/*   # sourceURL=here   */", None),
+    ];
+
+    for test in tests {
+        let mut input = ParserInput::new(test.0);
+        let mut parser = Parser::new(&mut input);
+        while parser.next_including_whitespace().is_ok() {}
+        assert_eq!(parser.current_source_url(), test.1);
+    }
+}
+
+#[cfg_attr(all(miri, feature = "skip_long_tests"), ignore)]
+#[test]
+fn roundtrip_percentage_token() {
+    fn test_roundtrip(value: &str) {
+        let mut input = ParserInput::new(value);
+        let mut parser = Parser::new(&mut input);
+        let token = parser.next().unwrap();
+        assert_eq!(token.to_css_string(), value);
+    }
+    // Test simple number serialization
+    for i in 0..101 {
+        test_roundtrip(&format!("{}%", i));
+        for j in 0..10 {
+            if j != 0 {
+                test_roundtrip(&format!("{}.{}%", i, j));
+            }
+            for k in 1..10 {
+                test_roundtrip(&format!("{}.{}{}%", i, j, k));
+            }
+        }
+    }
+}
+
+#[test]
+fn utf16_columns() {
+    // This particular test serves two purposes.  First, it checks
+    // that the column number computations are correct.  Second, it
+    // checks that tokenizer code paths correctly differentiate
+    // between the different UTF-8 encoding bytes.  In particular
+    // different leader bytes and continuation bytes are treated
+    // differently, so we make sure to include all lengths in the
+    // tests, using the string "QΡ✈🆒".  Also, remember that because
+    // the column is in units of UTF-16, the 4-byte sequence results
+    // in two columns.
+    let tests = vec![
+        ("", 1),
+        ("ascii", 6),
+        ("/*QΡ✈🆒*/", 10),
+        ("'QΡ✈🆒*'", 9),
+        ("\"\\\"'QΡ✈🆒*'", 12),
+        ("\\Q\\Ρ\\✈\\🆒", 10),
+        ("QΡ✈🆒", 6),
+        ("QΡ✈🆒\\Q\\Ρ\\✈\\🆒", 15),
+        ("newline\r\nQΡ✈🆒", 6),
+        ("url(QΡ✈🆒\\Q\\Ρ\\✈\\🆒)", 20),
+        ("url(QΡ✈🆒)", 11),
+        ("url(\r\nQΡ✈🆒\\Q\\Ρ\\✈\\🆒)", 16),
+        ("url(\r\nQΡ✈🆒\\Q\\Ρ\\✈\\🆒", 15),
+        ("url(\r\nQΡ✈🆒\\Q\\Ρ\\✈\\🆒 x", 17),
+        ("QΡ✈🆒()", 8),
+        // Test that under/over-flow of current_line_start_position is
+        // handled properly; see the special case in consume_4byte_intro.
+        ("🆒", 3),
+    ];
+
+    for test in tests {
+        let mut input = ParserInput::new(test.0);
+        let mut parser = Parser::new(&mut input);
+
+        // Read all tokens.
+        loop {
+            match parser.next() {
+                Err(BasicParseError {
+                    kind: BasicParseErrorKind::EndOfInput,
+                    ..
+                }) => {
+                    break;
+                }
+                Err(_) => {
+                    // should this be an explicit panic instead?
+                    unreachable!();
+                }
+                Ok(_) => {}
+            };
+        }
+
+        // Check the resulting column.
+        assert_eq!(parser.current_source_location().column, test.1);
+    }
+}
+
+#[test]
+fn servo_define_css_keyword_enum() {
+    macro_rules! define_css_keyword_enum {
+        (pub enum $name:ident { $($variant:ident = $css:pat,)+ }) => {
+            #[derive(PartialEq, Debug)]
+            pub enum $name {
+                $($variant),+
+            }
+
+            impl $name {
+                pub fn from_ident(ident: &str) -> Result<$name, ()> {
+                    match_ignore_ascii_case! { ident,
+                        $($css => Ok($name::$variant),)+
+                        _ => Err(())
+                    }
+                }
+            }
+        }
+    }
+    define_css_keyword_enum! {
+        pub enum UserZoom {
+            Zoom = "zoom",
+            Fixed = "fixed",
+        }
+    }
+
+    assert_eq!(UserZoom::from_ident("fixed"), Ok(UserZoom::Fixed));
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tokenizer.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tokenizer.rs
new file mode 100644
index 000000000000..ea173a5e457e
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tokenizer.rs
@@ -0,0 +1,1407 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://drafts.csswg.org/css-syntax/#tokenization
+
+use self::Token::*;
+use crate::cow_rc_str::CowRcStr;
+use crate::parser::ParserState;
+use std::char;
+use std::ops::Range;
+
+#[cfg(not(feature = "dummy_match_byte"))]
+use cssparser_macros::match_byte;
+
+#[cfg(feature = "dummy_match_byte")]
+macro_rules! match_byte {
+    ($value:expr, $($rest:tt)* ) => {
+        match $value {
+            $(
+                $rest
+            )+
+        }
+    };
+}
+
+/// One of the pieces the CSS input is broken into.
+///
+/// Some components use `Cow` in order to borrow from the original input string
+/// and avoid allocating/copying when possible.
+#[derive(PartialEq, Debug, Clone)]
+pub enum Token<'a> {
+    /// A [`<ident-token>`](https://drafts.csswg.org/css-syntax/#ident-token-diagram)
+    Ident(CowRcStr<'a>),
+
+    /// A [`<at-keyword-token>`](https://drafts.csswg.org/css-syntax/#at-keyword-token-diagram)
+    ///
+    /// The value does not include the `@` marker.
+    AtKeyword(CowRcStr<'a>),
+
+    /// A [`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with the type flag set to "unrestricted"
+    ///
+    /// The value does not include the `#` marker.
+    Hash(CowRcStr<'a>),
+
+    /// A [`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with the type flag set to "id"
+    ///
+    /// The value does not include the `#` marker.
+    IDHash(CowRcStr<'a>), // Hash that is a valid ID selector.
+
+    /// A [`<string-token>`](https://drafts.csswg.org/css-syntax/#string-token-diagram)
+    ///
+    /// The value does not include the quotes.
+    QuotedString(CowRcStr<'a>),
+
+    /// A [`<url-token>`](https://drafts.csswg.org/css-syntax/#url-token-diagram)
+    ///
+    /// The value does not include the `url(` `)` markers.  Note that `url( <string-token> )` is represented by a
+    /// `Function` token.
+    UnquotedUrl(CowRcStr<'a>),
+
+    /// A `<delim-token>`
+    Delim(char),
+
+    /// A [`<number-token>`](https://drafts.csswg.org/css-syntax/#number-token-diagram)
+    Number {
+        /// Whether the number had a `+` or `-` sign.
+        ///
+        /// This is used is some cases like the <An+B> micro syntax. (See the `parse_nth` function.)
+        has_sign: bool,
+
+        /// The value as a float
+        value: f32,
+
+        /// If the origin source did not include a fractional part, the value as an integer.
+        int_value: Option<i32>,
+    },
+
+    /// A [`<percentage-token>`](https://drafts.csswg.org/css-syntax/#percentage-token-diagram)
+    Percentage {
+        /// Whether the number had a `+` or `-` sign.
+        has_sign: bool,
+
+        /// The value as a float, divided by 100 so that the nominal range is 0.0 to 1.0.
+        unit_value: f32,
+
+        /// If the origin source did not include a fractional part, the value as an integer.
+        /// It is **not** divided by 100.
+        int_value: Option<i32>,
+    },
+
+    /// A [`<dimension-token>`](https://drafts.csswg.org/css-syntax/#dimension-token-diagram)
+    Dimension {
+        /// Whether the number had a `+` or `-` sign.
+        ///
+        /// This is used is some cases like the <An+B> micro syntax. (See the `parse_nth` function.)
+        has_sign: bool,
+
+        /// The value as a float
+        value: f32,
+
+        /// If the origin source did not include a fractional part, the value as an integer.
+        int_value: Option<i32>,
+
+        /// The unit, e.g. "px" in `12px`
+        unit: CowRcStr<'a>,
+    },
+
+    /// A [`<whitespace-token>`](https://drafts.csswg.org/css-syntax/#whitespace-token-diagram)
+    WhiteSpace(&'a str),
+
+    /// A comment.
+    ///
+    /// The CSS Syntax spec does not generate tokens for comments,
+    /// But we do, because we can (borrowed &str makes it cheap).
+    ///
+    /// The value does not include the `/*` `*/` markers.
+    Comment(&'a str),
+
+    /// A `:` `<colon-token>`
+    Colon, // :
+
+    /// A `;` `<semicolon-token>`
+    Semicolon, // ;
+
+    /// A `,` `<comma-token>`
+    Comma, // ,
+
+    /// A `~=` [`<include-match-token>`](https://drafts.csswg.org/css-syntax/#include-match-token-diagram)
+    IncludeMatch,
+
+    /// A `|=` [`<dash-match-token>`](https://drafts.csswg.org/css-syntax/#dash-match-token-diagram)
+    DashMatch,
+
+    /// A `^=` [`<prefix-match-token>`](https://drafts.csswg.org/css-syntax/#prefix-match-token-diagram)
+    PrefixMatch,
+
+    /// A `$=` [`<suffix-match-token>`](https://drafts.csswg.org/css-syntax/#suffix-match-token-diagram)
+    SuffixMatch,
+
+    /// A `*=` [`<substring-match-token>`](https://drafts.csswg.org/css-syntax/#substring-match-token-diagram)
+    SubstringMatch,
+
+    /// A `<!--` [`<CDO-token>`](https://drafts.csswg.org/css-syntax/#CDO-token-diagram)
+    CDO,
+
+    /// A `-->` [`<CDC-token>`](https://drafts.csswg.org/css-syntax/#CDC-token-diagram)
+    CDC,
+
+    /// A [`<function-token>`](https://drafts.csswg.org/css-syntax/#function-token-diagram)
+    ///
+    /// The value (name) does not include the `(` marker.
+    Function(CowRcStr<'a>),
+
+    /// A `<(-token>`
+    ParenthesisBlock,
+
+    /// A `<[-token>`
+    SquareBracketBlock,
+
+    /// A `<{-token>`
+    CurlyBracketBlock,
+
+    /// A `<bad-url-token>`
+    ///
+    /// This token always indicates a parse error.
+    BadUrl(CowRcStr<'a>),
+
+    /// A `<bad-string-token>`
+    ///
+    /// This token always indicates a parse error.
+    BadString(CowRcStr<'a>),
+
+    /// A `<)-token>`
+    ///
+    /// When obtained from one of the `Parser::next*` methods,
+    /// this token is always unmatched and indicates a parse error.
+    CloseParenthesis,
+
+    /// A `<]-token>`
+    ///
+    /// When obtained from one of the `Parser::next*` methods,
+    /// this token is always unmatched and indicates a parse error.
+    CloseSquareBracket,
+
+    /// A `<}-token>`
+    ///
+    /// When obtained from one of the `Parser::next*` methods,
+    /// this token is always unmatched and indicates a parse error.
+    CloseCurlyBracket,
+}
+
+impl<'a> Token<'a> {
+    /// Return whether this token represents a parse error.
+    ///
+    /// `BadUrl` and `BadString` are tokenizer-level parse errors.
+    ///
+    /// `CloseParenthesis`, `CloseSquareBracket`, and `CloseCurlyBracket` are *unmatched*
+    /// and therefore parse errors when returned by one of the `Parser::next*` methods.
+    pub fn is_parse_error(&self) -> bool {
+        matches!(
+            *self,
+            BadUrl(_) | BadString(_) | CloseParenthesis | CloseSquareBracket | CloseCurlyBracket
+        )
+    }
+}
+
+#[derive(Clone)]
+pub struct Tokenizer<'a> {
+    input: &'a str,
+    /// Counted in bytes, not code points. From 0.
+    position: usize,
+    /// The position at the start of the current line; but adjusted to
+    /// ensure that computing the column will give the result in units
+    /// of UTF-16 characters.
+    current_line_start_position: usize,
+    current_line_number: u32,
+    var_or_env_functions: SeenStatus,
+    source_map_url: Option<&'a str>,
+    source_url: Option<&'a str>,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+enum SeenStatus {
+    DontCare,
+    LookingForThem,
+    SeenAtLeastOne,
+}
+
+impl<'a> Tokenizer<'a> {
+    #[inline]
+    pub fn new(input: &str) -> Tokenizer {
+        Tokenizer {
+            input,
+            position: 0,
+            current_line_start_position: 0,
+            current_line_number: 0,
+            var_or_env_functions: SeenStatus::DontCare,
+            source_map_url: None,
+            source_url: None,
+        }
+    }
+
+    #[inline]
+    pub fn look_for_var_or_env_functions(&mut self) {
+        self.var_or_env_functions = SeenStatus::LookingForThem;
+    }
+
+    #[inline]
+    pub fn seen_var_or_env_functions(&mut self) -> bool {
+        let seen = self.var_or_env_functions == SeenStatus::SeenAtLeastOne;
+        self.var_or_env_functions = SeenStatus::DontCare;
+        seen
+    }
+
+    #[inline]
+    pub fn see_function(&mut self, name: &str) {
+        if self.var_or_env_functions == SeenStatus::LookingForThem
+            && (name.eq_ignore_ascii_case("var") || name.eq_ignore_ascii_case("env"))
+        {
+            self.var_or_env_functions = SeenStatus::SeenAtLeastOne;
+        }
+    }
+
+    #[inline]
+    pub fn next(&mut self) -> Result<Token<'a>, ()> {
+        next_token(self)
+    }
+
+    #[inline]
+    pub fn position(&self) -> SourcePosition {
+        debug_assert!(self.input.is_char_boundary(self.position));
+        SourcePosition(self.position)
+    }
+
+    #[inline]
+    pub fn current_source_location(&self) -> SourceLocation {
+        SourceLocation {
+            line: self.current_line_number,
+            column: (self.position - self.current_line_start_position + 1) as u32,
+        }
+    }
+
+    #[inline]
+    pub fn current_source_map_url(&self) -> Option<&'a str> {
+        self.source_map_url
+    }
+
+    #[inline]
+    pub fn current_source_url(&self) -> Option<&'a str> {
+        self.source_url
+    }
+
+    #[inline]
+    pub fn state(&self) -> ParserState {
+        ParserState {
+            position: self.position,
+            current_line_start_position: self.current_line_start_position,
+            current_line_number: self.current_line_number,
+            at_start_of: None,
+        }
+    }
+
+    #[inline]
+    pub fn reset(&mut self, state: &ParserState) {
+        self.position = state.position;
+        self.current_line_start_position = state.current_line_start_position;
+        self.current_line_number = state.current_line_number;
+    }
+
+    #[inline]
+    pub(crate) fn slice_from(&self, start_pos: SourcePosition) -> &'a str {
+        self.slice(start_pos..self.position())
+    }
+
+    #[inline]
+    pub(crate) fn slice(&self, range: Range<SourcePosition>) -> &'a str {
+        debug_assert!(self.input.is_char_boundary(range.start.0));
+        debug_assert!(self.input.is_char_boundary(range.end.0));
+        unsafe { self.input.get_unchecked(range.start.0..range.end.0) }
+    }
+
+    pub fn current_source_line(&self) -> &'a str {
+        let current = self.position();
+        let start = self
+            .slice(SourcePosition(0)..current)
+            .rfind(|c| matches!(c, '\r' | '\n' | '\x0C'))
+            .map_or(0, |start| start + 1);
+        let end = self
+            .slice(current..SourcePosition(self.input.len()))
+            .find(|c| matches!(c, '\r' | '\n' | '\x0C'))
+            .map_or(self.input.len(), |end| current.0 + end);
+        self.slice(SourcePosition(start)..SourcePosition(end))
+    }
+
+    #[inline]
+    pub fn next_byte(&self) -> Option<u8> {
+        if self.is_eof() {
+            None
+        } else {
+            Some(self.input.as_bytes()[self.position])
+        }
+    }
+
+    // If false, `tokenizer.next_char()` will not panic.
+    #[inline]
+    fn is_eof(&self) -> bool {
+        !self.has_at_least(0)
+    }
+
+    // If true, the input has at least `n` bytes left *after* the current one.
+    // That is, `tokenizer.char_at(n)` will not panic.
+    #[inline]
+    fn has_at_least(&self, n: usize) -> bool {
+        self.position + n < self.input.len()
+    }
+
+    // Advance over N bytes in the input.  This function can advance
+    // over ASCII bytes (excluding newlines), or UTF-8 sequence
+    // leaders (excluding leaders for 4-byte sequences).
+    #[inline]
+    pub fn advance(&mut self, n: usize) {
+        if cfg!(debug_assertions) {
+            // Each byte must either be an ASCII byte or a sequence
+            // leader, but not a 4-byte leader; also newlines are
+            // rejected.
+            for i in 0..n {
+                let b = self.byte_at(i);
+                debug_assert!(b.is_ascii() || (b & 0xF0 != 0xF0 && b & 0xC0 != 0x80));
+                debug_assert!(b != b'\r' && b != b'\n' && b != b'\x0C');
+            }
+        }
+        self.position += n
+    }
+
+    // Assumes non-EOF
+    #[inline]
+    fn next_byte_unchecked(&self) -> u8 {
+        self.byte_at(0)
+    }
+
+    #[inline]
+    fn byte_at(&self, offset: usize) -> u8 {
+        self.input.as_bytes()[self.position + offset]
+    }
+
+    // Advance over a single byte; the byte must be a UTF-8 sequence
+    // leader for a 4-byte sequence.
+    #[inline]
+    fn consume_4byte_intro(&mut self) {
+        debug_assert!(self.next_byte_unchecked() & 0xF0 == 0xF0);
+        // This takes two UTF-16 characters to represent, so we
+        // actually have an undercount.
+        self.current_line_start_position = self.current_line_start_position.wrapping_sub(1);
+        self.position += 1;
+    }
+
+    // Advance over a single byte; the byte must be a UTF-8
+    // continuation byte.
+    #[inline]
+    fn consume_continuation_byte(&mut self) {
+        debug_assert!(self.next_byte_unchecked() & 0xC0 == 0x80);
+        // Continuation bytes contribute to column overcount.  Note
+        // that due to the special case for the 4-byte sequence intro,
+        // we must use wrapping add here.
+        self.current_line_start_position = self.current_line_start_position.wrapping_add(1);
+        self.position += 1;
+    }
+
+    // Advance over any kind of byte, excluding newlines.
+    #[inline(never)]
+    fn consume_known_byte(&mut self, byte: u8) {
+        debug_assert!(byte != b'\r' && byte != b'\n' && byte != b'\x0C');
+        self.position += 1;
+        // Continuation bytes contribute to column overcount.
+        if byte & 0xF0 == 0xF0 {
+            // This takes two UTF-16 characters to represent, so we
+            // actually have an undercount.
+            self.current_line_start_position = self.current_line_start_position.wrapping_sub(1);
+        } else if byte & 0xC0 == 0x80 {
+            // Note that due to the special case for the 4-byte
+            // sequence intro, we must use wrapping add here.
+            self.current_line_start_position = self.current_line_start_position.wrapping_add(1);
+        }
+    }
+
+    #[inline]
+    fn next_char(&self) -> char {
+        unsafe { self.input.get_unchecked(self.position().0..) }
+            .chars()
+            .next()
+            .unwrap()
+    }
+
+    // Given that a newline has been seen, advance over the newline
+    // and update the state.
+    #[inline]
+    fn consume_newline(&mut self) {
+        let byte = self.next_byte_unchecked();
+        debug_assert!(byte == b'\r' || byte == b'\n' || byte == b'\x0C');
+        self.position += 1;
+        if byte == b'\r' && self.next_byte() == Some(b'\n') {
+            self.position += 1;
+        }
+        self.current_line_start_position = self.position;
+        self.current_line_number += 1;
+    }
+
+    #[inline]
+    fn has_newline_at(&self, offset: usize) -> bool {
+        self.position + offset < self.input.len()
+            && matches!(self.byte_at(offset), b'\n' | b'\r' | b'\x0C')
+    }
+
+    #[inline]
+    fn consume_char(&mut self) -> char {
+        let c = self.next_char();
+        let len_utf8 = c.len_utf8();
+        self.position += len_utf8;
+        // Note that due to the special case for the 4-byte sequence
+        // intro, we must use wrapping add here.
+        self.current_line_start_position = self
+            .current_line_start_position
+            .wrapping_add(len_utf8 - c.len_utf16());
+        c
+    }
+
+    #[inline]
+    fn starts_with(&self, needle: &[u8]) -> bool {
+        self.input.as_bytes()[self.position..].starts_with(needle)
+    }
+
+    pub fn skip_whitespace(&mut self) {
+        while !self.is_eof() {
+            match_byte! { self.next_byte_unchecked(),
+                b' ' | b'\t' => {
+                    self.advance(1)
+                },
+                b'\n' | b'\x0C' | b'\r' => {
+                    self.consume_newline();
+                },
+                b'/' => {
+                    if self.starts_with(b"/*") {
+                        consume_comment(self);
+                    } else {
+                        return
+                    }
+                }
+                _ => return,
+            }
+        }
+    }
+
+    pub fn skip_cdc_and_cdo(&mut self) {
+        while !self.is_eof() {
+            match_byte! { self.next_byte_unchecked(),
+                b' ' | b'\t' => {
+                    self.advance(1)
+                },
+                b'\n' | b'\x0C' | b'\r' => {
+                    self.consume_newline();
+                },
+                b'/' => {
+                    if self.starts_with(b"/*") {
+                        consume_comment(self);
+                    } else {
+                        return
+                    }
+                }
+                b'<' => {
+                    if self.starts_with(b"<!--") {
+                        self.advance(4)
+                    } else {
+                        return
+                    }
+                }
+                b'-' => {
+                    if self.starts_with(b"-->") {
+                        self.advance(3)
+                    } else {
+                        return
+                    }
+                }
+                _ => {
+                    return
+                }
+            }
+        }
+    }
+}
+
+/// A position from the start of the input, counted in UTF-8 bytes.
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
+pub struct SourcePosition(pub(crate) usize);
+
+impl SourcePosition {
+    /// Returns the current byte index in the original input.
+    #[inline]
+    pub fn byte_index(&self) -> usize {
+        self.0
+    }
+}
+
+/// The line and column number for a given position within the input.
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub struct SourceLocation {
+    /// The line number, starting at 0 for the first line.
+    pub line: u32,
+
+    /// The column number within a line, starting at 1 for first the character of the line.
+    /// Column numbers are counted in UTF-16 code units.
+    pub column: u32,
+}
+
+fn next_token<'a>(tokenizer: &mut Tokenizer<'a>) -> Result<Token<'a>, ()> {
+    if tokenizer.is_eof() {
+        return Err(());
+    }
+    let b = tokenizer.next_byte_unchecked();
+    let token = match_byte! { b,
+        b' ' | b'\t' => {
+            consume_whitespace(tokenizer, false)
+        },
+        b'\n' | b'\x0C' | b'\r' => consume_whitespace(tokenizer, true),
+        b'"' => consume_string(tokenizer, false),
+        b'#' => {
+            tokenizer.advance(1);
+            if is_ident_start(tokenizer) { IDHash(consume_name(tokenizer)) }
+            else if !tokenizer.is_eof() &&
+                matches!(tokenizer.next_byte_unchecked(), b'0'..=b'9' | b'-') {
+                // Any other valid case here already resulted in IDHash.
+                Hash(consume_name(tokenizer))
+            }
+            else { Delim('#') }
+        },
+        b'$' => {
+            if tokenizer.starts_with(b"$=") { tokenizer.advance(2); SuffixMatch }
+            else { tokenizer.advance(1); Delim('$') }
+        },
+        b'\'' => consume_string(tokenizer, true),
+        b'(' => { tokenizer.advance(1); ParenthesisBlock },
+        b')' => { tokenizer.advance(1); CloseParenthesis },
+        b'*' => {
+            if tokenizer.starts_with(b"*=") { tokenizer.advance(2); SubstringMatch }
+            else { tokenizer.advance(1); Delim('*') }
+        },
+        b'+' => {
+            if (
+                tokenizer.has_at_least(1)
+                && tokenizer.byte_at(1).is_ascii_digit()
+            ) || (
+                tokenizer.has_at_least(2)
+                && tokenizer.byte_at(1) == b'.'
+                && tokenizer.byte_at(2).is_ascii_digit()
+            ) {
+                consume_numeric(tokenizer)
+            } else {
+                tokenizer.advance(1);
+                Delim('+')
+            }
+        },
+        b',' => { tokenizer.advance(1); Comma },
+        b'-' => {
+            if (
+                tokenizer.has_at_least(1)
+                && tokenizer.byte_at(1).is_ascii_digit()
+            ) || (
+                tokenizer.has_at_least(2)
+                && tokenizer.byte_at(1) == b'.'
+                && tokenizer.byte_at(2).is_ascii_digit()
+            ) {
+                consume_numeric(tokenizer)
+            } else if tokenizer.starts_with(b"-->") {
+                tokenizer.advance(3);
+                CDC
+            } else if is_ident_start(tokenizer) {
+                consume_ident_like(tokenizer)
+            } else {
+                tokenizer.advance(1);
+                Delim('-')
+            }
+        },
+        b'.' => {
+            if tokenizer.has_at_least(1)
+                && tokenizer.byte_at(1).is_ascii_digit() {
+                consume_numeric(tokenizer)
+            } else {
+                tokenizer.advance(1);
+                Delim('.')
+            }
+        }
+        b'/' => {
+            if tokenizer.starts_with(b"/*") {
+                Comment(consume_comment(tokenizer))
+            } else {
+                tokenizer.advance(1);
+                Delim('/')
+            }
+        }
+        b'0'..=b'9' => consume_numeric(tokenizer),
+        b':' => { tokenizer.advance(1); Colon },
+        b';' => { tokenizer.advance(1); Semicolon },
+        b'<' => {
+            if tokenizer.starts_with(b"<!--") {
+                tokenizer.advance(4);
+                CDO
+            } else {
+                tokenizer.advance(1);
+                Delim('<')
+            }
+        },
+        b'@' => {
+            tokenizer.advance(1);
+            if is_ident_start(tokenizer) { AtKeyword(consume_name(tokenizer)) }
+            else { Delim('@') }
+        },
+        b'a'..=b'z' | b'A'..=b'Z' | b'_' | b'\0' => consume_ident_like(tokenizer),
+        b'[' => { tokenizer.advance(1); SquareBracketBlock },
+        b'\\' => {
+            if !tokenizer.has_newline_at(1) { consume_ident_like(tokenizer) }
+            else { tokenizer.advance(1); Delim('\\') }
+        },
+        b']' => { tokenizer.advance(1); CloseSquareBracket },
+        b'^' => {
+            if tokenizer.starts_with(b"^=") { tokenizer.advance(2); PrefixMatch }
+            else { tokenizer.advance(1); Delim('^') }
+        },
+        b'{' => { tokenizer.advance(1); CurlyBracketBlock },
+        b'|' => {
+            if tokenizer.starts_with(b"|=") { tokenizer.advance(2); DashMatch }
+            else { tokenizer.advance(1); Delim('|') }
+        },
+        b'}' => { tokenizer.advance(1); CloseCurlyBracket },
+        b'~' => {
+            if tokenizer.starts_with(b"~=") { tokenizer.advance(2); IncludeMatch }
+            else { tokenizer.advance(1); Delim('~') }
+        },
+        _ => {
+            if !b.is_ascii() {
+                consume_ident_like(tokenizer)
+            } else {
+                tokenizer.advance(1);
+                Delim(b as char)
+            }
+        },
+    };
+    Ok(token)
+}
+
+fn consume_whitespace<'a>(tokenizer: &mut Tokenizer<'a>, newline: bool) -> Token<'a> {
+    let start_position = tokenizer.position();
+    if newline {
+        tokenizer.consume_newline();
+    } else {
+        tokenizer.advance(1);
+    }
+    while !tokenizer.is_eof() {
+        let b = tokenizer.next_byte_unchecked();
+        match_byte! { b,
+            b' ' | b'\t' => {
+                tokenizer.advance(1);
+            }
+            b'\n' | b'\x0C' | b'\r' => {
+                tokenizer.consume_newline();
+            }
+            _ => {
+                break
+            }
+        }
+    }
+    WhiteSpace(tokenizer.slice_from(start_position))
+}
+
+// Check for sourceMappingURL or sourceURL comments and update the
+// tokenizer appropriately.
+fn check_for_source_map<'a>(tokenizer: &mut Tokenizer<'a>, contents: &'a str) {
+    let directive = "# sourceMappingURL=";
+    let directive_old = "@ sourceMappingURL=";
+
+    // If there is a source map directive, extract the URL.
+    if contents.starts_with(directive) || contents.starts_with(directive_old) {
+        let contents = &contents[directive.len()..];
+        tokenizer.source_map_url = contents
+            .split(|c| c == ' ' || c == '\t' || c == '\x0C' || c == '\r' || c == '\n')
+            .next()
+    }
+
+    let directive = "# sourceURL=";
+    let directive_old = "@ sourceURL=";
+
+    // If there is a source map directive, extract the URL.
+    if contents.starts_with(directive) || contents.starts_with(directive_old) {
+        let contents = &contents[directive.len()..];
+        tokenizer.source_url = contents
+            .split(|c| c == ' ' || c == '\t' || c == '\x0C' || c == '\r' || c == '\n')
+            .next()
+    }
+}
+
+fn consume_comment<'a>(tokenizer: &mut Tokenizer<'a>) -> &'a str {
+    tokenizer.advance(2); // consume "/*"
+    let start_position = tokenizer.position();
+    while !tokenizer.is_eof() {
+        match_byte! { tokenizer.next_byte_unchecked(),
+            b'*' => {
+                let end_position = tokenizer.position();
+                tokenizer.advance(1);
+                if tokenizer.next_byte() == Some(b'/') {
+                    tokenizer.advance(1);
+                    let contents = tokenizer.slice(start_position..end_position);
+                    check_for_source_map(tokenizer, contents);
+                    return contents
+                }
+            }
+            b'\n' | b'\x0C' | b'\r' => {
+                tokenizer.consume_newline();
+            }
+            b'\x80'..=b'\xBF' => { tokenizer.consume_continuation_byte(); }
+            b'\xF0'..=b'\xFF' => { tokenizer.consume_4byte_intro(); }
+            _ => {
+                // ASCII or other leading byte.
+                tokenizer.advance(1);
+            }
+        }
+    }
+    let contents = tokenizer.slice_from(start_position);
+    check_for_source_map(tokenizer, contents);
+    contents
+}
+
+fn consume_string<'a>(tokenizer: &mut Tokenizer<'a>, single_quote: bool) -> Token<'a> {
+    match consume_quoted_string(tokenizer, single_quote) {
+        Ok(value) => QuotedString(value),
+        Err(value) => BadString(value),
+    }
+}
+
+/// Return `Err(())` on syntax error (ie. unescaped newline)
+fn consume_quoted_string<'a>(
+    tokenizer: &mut Tokenizer<'a>,
+    single_quote: bool,
+) -> Result<CowRcStr<'a>, CowRcStr<'a>> {
+    tokenizer.advance(1); // Skip the initial quote
+                          // start_pos is at code point boundary, after " or '
+    let start_pos = tokenizer.position();
+    let mut string_bytes;
+    loop {
+        if tokenizer.is_eof() {
+            return Ok(tokenizer.slice_from(start_pos).into());
+        }
+        match_byte! { tokenizer.next_byte_unchecked(),
+            b'"' => {
+                if !single_quote {
+                    let value = tokenizer.slice_from(start_pos);
+                    tokenizer.advance(1);
+                    return Ok(value.into())
+                }
+                tokenizer.advance(1);
+            }
+            b'\'' => {
+                if single_quote {
+                    let value = tokenizer.slice_from(start_pos);
+                    tokenizer.advance(1);
+                    return Ok(value.into())
+                }
+                tokenizer.advance(1);
+            }
+            b'\\' | b'\0' => {
+                // * The tokenizer’s input is UTF-8 since it’s `&str`.
+                // * start_pos is at a code point boundary
+                // * so is the current position (which is before '\\' or '\0'
+                //
+                // So `string_bytes` is well-formed UTF-8.
+                string_bytes = tokenizer.slice_from(start_pos).as_bytes().to_owned();
+                break
+            }
+            b'\n' | b'\r' | b'\x0C' => {
+                return Err(tokenizer.slice_from(start_pos).into())
+            },
+            b'\x80'..=b'\xBF' => { tokenizer.consume_continuation_byte(); }
+            b'\xF0'..=b'\xFF' => { tokenizer.consume_4byte_intro(); }
+            _ => {
+                // ASCII or other leading byte.
+                tokenizer.advance(1);
+            }
+        }
+    }
+
+    while !tokenizer.is_eof() {
+        let b = tokenizer.next_byte_unchecked();
+        match_byte! { b,
+            b'\n' | b'\r' | b'\x0C' => {
+                return Err(
+                    // string_bytes is well-formed UTF-8, see other comments.
+                    unsafe {
+                        from_utf8_release_unchecked(string_bytes)
+                    }.into()
+                );
+            }
+            b'"' => {
+                tokenizer.advance(1);
+                if !single_quote {
+                    break;
+                }
+            }
+            b'\'' => {
+                tokenizer.advance(1);
+                if single_quote {
+                    break;
+                }
+            }
+            b'\\' => {
+                tokenizer.advance(1);
+                if !tokenizer.is_eof() {
+                    match tokenizer.next_byte_unchecked() {
+                        // Escaped newline
+                        b'\n' | b'\x0C' | b'\r' => {
+                            tokenizer.consume_newline();
+                        }
+                        // This pushes one well-formed code point
+                        _ => consume_escape_and_write(tokenizer, &mut string_bytes)
+                    }
+                }
+                // else: escaped EOF, do nothing.
+                continue;
+            }
+            b'\0' => {
+                tokenizer.advance(1);
+                string_bytes.extend("\u{FFFD}".as_bytes());
+                continue;
+            }
+            b'\x80'..=b'\xBF' => { tokenizer.consume_continuation_byte(); }
+            b'\xF0'..=b'\xFF' => { tokenizer.consume_4byte_intro(); }
+            _ => {
+                // ASCII or other leading byte.
+                tokenizer.advance(1);
+            },
+        }
+
+        // If this byte is part of a multi-byte code point,
+        // we’ll end up copying the whole code point before this loop does something else.
+        string_bytes.push(b);
+    }
+
+    Ok(
+        // string_bytes is well-formed UTF-8, see other comments.
+        unsafe { from_utf8_release_unchecked(string_bytes) }.into(),
+    )
+}
+
+#[inline]
+fn is_ident_start(tokenizer: &mut Tokenizer) -> bool {
+    !tokenizer.is_eof()
+        && match_byte! { tokenizer.next_byte_unchecked(),
+            b'a'..=b'z' | b'A'..=b'Z' | b'_' | b'\0' => true,
+            b'-' => {
+                tokenizer.has_at_least(1) && match_byte! { tokenizer.byte_at(1),
+                    b'a'..=b'z' | b'A'..=b'Z' | b'-' | b'_' | b'\0' => {
+                        true
+                    }
+                    b'\\' => !tokenizer.has_newline_at(1),
+                    b => !b.is_ascii(),
+                }
+            },
+            b'\\' => !tokenizer.has_newline_at(1),
+            b => !b.is_ascii(),
+        }
+}
+
+fn consume_ident_like<'a>(tokenizer: &mut Tokenizer<'a>) -> Token<'a> {
+    let value = consume_name(tokenizer);
+    if !tokenizer.is_eof() && tokenizer.next_byte_unchecked() == b'(' {
+        tokenizer.advance(1);
+        if value.eq_ignore_ascii_case("url") {
+            consume_unquoted_url(tokenizer).unwrap_or(Function(value))
+        } else {
+            tokenizer.see_function(&value);
+            Function(value)
+        }
+    } else {
+        Ident(value)
+    }
+}
+
+fn consume_name<'a>(tokenizer: &mut Tokenizer<'a>) -> CowRcStr<'a> {
+    // start_pos is the end of the previous token, therefore at a code point boundary
+    let start_pos = tokenizer.position();
+    let mut value_bytes;
+    loop {
+        if tokenizer.is_eof() {
+            return tokenizer.slice_from(start_pos).into();
+        }
+        match_byte! { tokenizer.next_byte_unchecked(),
+            b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' | b'_' | b'-' => tokenizer.advance(1),
+            b'\\' | b'\0' => {
+                // * The tokenizer’s input is UTF-8 since it’s `&str`.
+                // * start_pos is at a code point boundary
+                // * so is the current position (which is before '\\' or '\0'
+                //
+                // So `value_bytes` is well-formed UTF-8.
+                value_bytes = tokenizer.slice_from(start_pos).as_bytes().to_owned();
+                break
+            }
+            b'\x80'..=b'\xBF' => { tokenizer.consume_continuation_byte(); }
+            b'\xC0'..=b'\xEF' => { tokenizer.advance(1); }
+            b'\xF0'..=b'\xFF' => { tokenizer.consume_4byte_intro(); }
+            _b => {
+                return tokenizer.slice_from(start_pos).into();
+            }
+        }
+    }
+
+    while !tokenizer.is_eof() {
+        let b = tokenizer.next_byte_unchecked();
+        match_byte! { b,
+            b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' | b'_' | b'-'  => {
+                tokenizer.advance(1);
+                value_bytes.push(b)  // ASCII
+            }
+            b'\\' => {
+                if tokenizer.has_newline_at(1) { break }
+                tokenizer.advance(1);
+                // This pushes one well-formed code point
+                consume_escape_and_write(tokenizer, &mut value_bytes)
+            }
+            b'\0' => {
+                tokenizer.advance(1);
+                value_bytes.extend("\u{FFFD}".as_bytes());
+            },
+            b'\x80'..=b'\xBF' => {
+                // This byte *is* part of a multi-byte code point,
+                // we’ll end up copying the whole code point before this loop does something else.
+                tokenizer.consume_continuation_byte();
+                value_bytes.push(b)
+            }
+            b'\xC0'..=b'\xEF' => {
+                // This byte *is* part of a multi-byte code point,
+                // we’ll end up copying the whole code point before this loop does something else.
+                tokenizer.advance(1);
+                value_bytes.push(b)
+            }
+            b'\xF0'..=b'\xFF' => {
+                tokenizer.consume_4byte_intro();
+                value_bytes.push(b)
+            }
+            _ => {
+                // ASCII
+                break;
+            }
+        }
+    }
+    // string_bytes is well-formed UTF-8, see other comments.
+    unsafe { from_utf8_release_unchecked(value_bytes) }.into()
+}
+
+fn byte_to_hex_digit(b: u8) -> Option<u32> {
+    Some(match_byte! { b,
+        b'0' ..= b'9' => b - b'0',
+        b'a' ..= b'f' => b - b'a' + 10,
+        b'A' ..= b'F' => b - b'A' + 10,
+        _ => {
+            return None
+        }
+    } as u32)
+}
+
+fn byte_to_decimal_digit(b: u8) -> Option<u32> {
+    if b.is_ascii_digit() {
+        Some((b - b'0') as u32)
+    } else {
+        None
+    }
+}
+
+fn consume_numeric<'a>(tokenizer: &mut Tokenizer<'a>) -> Token<'a> {
+    // Parse [+-]?\d*(\.\d+)?([eE][+-]?\d+)?
+    // But this is always called so that there is at least one digit in \d*(\.\d+)?
+
+    // Do all the math in f64 so that large numbers overflow to +/-inf
+    // and i32::{MIN, MAX} are within range.
+
+    let (has_sign, sign) = match tokenizer.next_byte_unchecked() {
+        b'-' => (true, -1.),
+        b'+' => (true, 1.),
+        _ => (false, 1.),
+    };
+    if has_sign {
+        tokenizer.advance(1);
+    }
+
+    let mut integral_part: f64 = 0.;
+    while let Some(digit) = byte_to_decimal_digit(tokenizer.next_byte_unchecked()) {
+        integral_part = integral_part * 10. + digit as f64;
+        tokenizer.advance(1);
+        if tokenizer.is_eof() {
+            break;
+        }
+    }
+
+    let mut is_integer = true;
+
+    let mut fractional_part: f64 = 0.;
+    if tokenizer.has_at_least(1)
+        && tokenizer.next_byte_unchecked() == b'.'
+        && tokenizer.byte_at(1).is_ascii_digit()
+    {
+        is_integer = false;
+        tokenizer.advance(1); // Consume '.'
+        let mut factor = 0.1;
+        while let Some(digit) = byte_to_decimal_digit(tokenizer.next_byte_unchecked()) {
+            fractional_part += digit as f64 * factor;
+            factor *= 0.1;
+            tokenizer.advance(1);
+            if tokenizer.is_eof() {
+                break;
+            }
+        }
+    }
+
+    let mut value = sign * (integral_part + fractional_part);
+
+    if tokenizer.has_at_least(1)
+        && matches!(tokenizer.next_byte_unchecked(), b'e' | b'E')
+        && (tokenizer.byte_at(1).is_ascii_digit()
+            || (tokenizer.has_at_least(2)
+                && matches!(tokenizer.byte_at(1), b'+' | b'-')
+                && tokenizer.byte_at(2).is_ascii_digit()))
+    {
+        is_integer = false;
+        tokenizer.advance(1);
+        let (has_sign, sign) = match tokenizer.next_byte_unchecked() {
+            b'-' => (true, -1.),
+            b'+' => (true, 1.),
+            _ => (false, 1.),
+        };
+        if has_sign {
+            tokenizer.advance(1);
+        }
+        let mut exponent: f64 = 0.;
+        while let Some(digit) = byte_to_decimal_digit(tokenizer.next_byte_unchecked()) {
+            exponent = exponent * 10. + digit as f64;
+            tokenizer.advance(1);
+            if tokenizer.is_eof() {
+                break;
+            }
+        }
+        value *= f64::powf(10., sign * exponent);
+    }
+
+    let int_value = if is_integer {
+        Some(if value >= i32::MAX as f64 {
+            i32::MAX
+        } else if value <= i32::MIN as f64 {
+            i32::MIN
+        } else {
+            value as i32
+        })
+    } else {
+        None
+    };
+
+    if !tokenizer.is_eof() && tokenizer.next_byte_unchecked() == b'%' {
+        tokenizer.advance(1);
+        return Percentage {
+            unit_value: (value / 100.) as f32,
+            int_value,
+            has_sign,
+        };
+    }
+    let value = value as f32;
+    if is_ident_start(tokenizer) {
+        let unit = consume_name(tokenizer);
+        Dimension {
+            value,
+            int_value,
+            has_sign,
+            unit,
+        }
+    } else {
+        Number {
+            value,
+            int_value,
+            has_sign,
+        }
+    }
+}
+
+#[inline]
+unsafe fn from_utf8_release_unchecked(string_bytes: Vec<u8>) -> String {
+    if cfg!(debug_assertions) {
+        String::from_utf8(string_bytes).unwrap()
+    } else {
+        String::from_utf8_unchecked(string_bytes)
+    }
+}
+
+fn consume_unquoted_url<'a>(tokenizer: &mut Tokenizer<'a>) -> Result<Token<'a>, ()> {
+    // This is only called after "url(", so the current position is a code point boundary.
+    let start_position = tokenizer.position;
+    let from_start = &tokenizer.input[tokenizer.position..];
+    let mut newlines = 0;
+    let mut last_newline = 0;
+    let mut found_printable_char = false;
+    let mut iter = from_start.bytes().enumerate();
+    loop {
+        let (offset, b) = match iter.next() {
+            Some(item) => item,
+            None => {
+                tokenizer.position = tokenizer.input.len();
+                break;
+            }
+        };
+        match_byte! { b,
+            b' ' | b'\t' => {},
+            b'\n' | b'\x0C' => {
+                newlines += 1;
+                last_newline = offset;
+            }
+            b'\r' => {
+                if from_start.as_bytes().get(offset + 1) != Some(&b'\n') {
+                    newlines += 1;
+                    last_newline = offset;
+                }
+            }
+            b'"' | b'\'' => return Err(()),  // Do not advance
+            b')' => {
+                // Don't use advance, because we may be skipping
+                // newlines here, and we want to avoid the assert.
+                tokenizer.position += offset + 1;
+                break
+            }
+            _ => {
+                // Don't use advance, because we may be skipping
+                // newlines here, and we want to avoid the assert.
+                tokenizer.position += offset;
+                found_printable_char = true;
+                break
+            }
+        }
+    }
+
+    if newlines > 0 {
+        tokenizer.current_line_number += newlines;
+        // No need for wrapping_add here, because there's no possible
+        // way to wrap.
+        tokenizer.current_line_start_position = start_position + last_newline + 1;
+    }
+
+    if found_printable_char {
+        // This function only consumed ASCII (whitespace) bytes,
+        // so the current position is a code point boundary.
+        return Ok(consume_unquoted_url_internal(tokenizer));
+    } else {
+        return Ok(UnquotedUrl("".into()));
+    }
+
+    fn consume_unquoted_url_internal<'a>(tokenizer: &mut Tokenizer<'a>) -> Token<'a> {
+        // This function is only called with start_pos at a code point boundary.
+        let start_pos = tokenizer.position();
+        let mut string_bytes: Vec<u8>;
+        loop {
+            if tokenizer.is_eof() {
+                return UnquotedUrl(tokenizer.slice_from(start_pos).into());
+            }
+            match_byte! { tokenizer.next_byte_unchecked(),
+                b' ' | b'\t' | b'\n' | b'\r' | b'\x0C' => {
+                    let value = tokenizer.slice_from(start_pos);
+                    return consume_url_end(tokenizer, start_pos, value.into())
+                }
+                b')' => {
+                    let value = tokenizer.slice_from(start_pos);
+                    tokenizer.advance(1);
+                    return UnquotedUrl(value.into())
+                }
+                b'\x01'..=b'\x08' | b'\x0B' | b'\x0E'..=b'\x1F' | b'\x7F'  // non-printable
+                    | b'"' | b'\'' | b'(' => {
+                    tokenizer.advance(1);
+                    return consume_bad_url(tokenizer, start_pos)
+                },
+                b'\\' | b'\0' => {
+                    // * The tokenizer’s input is UTF-8 since it’s `&str`.
+                    // * start_pos is at a code point boundary
+                    // * so is the current position (which is before '\\' or '\0'
+                    //
+                    // So `string_bytes` is well-formed UTF-8.
+                    string_bytes = tokenizer.slice_from(start_pos).as_bytes().to_owned();
+                    break
+                }
+                b'\x80'..=b'\xBF' => { tokenizer.consume_continuation_byte(); }
+                b'\xF0'..=b'\xFF' => { tokenizer.consume_4byte_intro(); }
+                _ => {
+                    // ASCII or other leading byte.
+                    tokenizer.advance(1);
+                }
+            }
+        }
+        while !tokenizer.is_eof() {
+            let b = tokenizer.next_byte_unchecked();
+            match_byte! { b,
+                b' ' | b'\t' | b'\n' | b'\r' | b'\x0C' => {
+                    // string_bytes is well-formed UTF-8, see other comments.
+                    let string = unsafe { from_utf8_release_unchecked(string_bytes) }.into();
+                    return consume_url_end(tokenizer, start_pos, string)
+                }
+                b')' => {
+                    tokenizer.advance(1);
+                    break;
+                }
+                b'\x01'..=b'\x08' | b'\x0B' | b'\x0E'..=b'\x1F' | b'\x7F'  // non-printable
+                    | b'"' | b'\'' | b'(' => {
+                    tokenizer.advance(1);
+                    return consume_bad_url(tokenizer, start_pos);
+                }
+                b'\\' => {
+                    tokenizer.advance(1);
+                    if tokenizer.has_newline_at(0) {
+                        return consume_bad_url(tokenizer, start_pos)
+                    }
+
+                    // This pushes one well-formed code point to string_bytes
+                    consume_escape_and_write(tokenizer, &mut string_bytes)
+                },
+                b'\0' => {
+                    tokenizer.advance(1);
+                    string_bytes.extend("\u{FFFD}".as_bytes());
+                }
+                b'\x80'..=b'\xBF' => {
+                    // We’ll end up copying the whole code point
+                    // before this loop does something else.
+                    tokenizer.consume_continuation_byte();
+                    string_bytes.push(b);
+                }
+                b'\xF0'..=b'\xFF' => {
+                    // We’ll end up copying the whole code point
+                    // before this loop does something else.
+                    tokenizer.consume_4byte_intro();
+                    string_bytes.push(b);
+                }
+                // If this byte is part of a multi-byte code point,
+                // we’ll end up copying the whole code point before this loop does something else.
+                b => {
+                    // ASCII or other leading byte.
+                    tokenizer.advance(1);
+                    string_bytes.push(b)
+                }
+            }
+        }
+        UnquotedUrl(
+            // string_bytes is well-formed UTF-8, see other comments.
+            unsafe { from_utf8_release_unchecked(string_bytes) }.into(),
+        )
+    }
+
+    fn consume_url_end<'a>(
+        tokenizer: &mut Tokenizer<'a>,
+        start_pos: SourcePosition,
+        string: CowRcStr<'a>,
+    ) -> Token<'a> {
+        while !tokenizer.is_eof() {
+            match_byte! { tokenizer.next_byte_unchecked(),
+                b')' => {
+                    tokenizer.advance(1);
+                    break
+                }
+                b' ' | b'\t' => { tokenizer.advance(1); }
+                b'\n' | b'\x0C' | b'\r' => {
+                    tokenizer.consume_newline();
+                }
+                b => {
+                    tokenizer.consume_known_byte(b);
+                    return consume_bad_url(tokenizer, start_pos);
+                }
+            }
+        }
+        UnquotedUrl(string)
+    }
+
+    fn consume_bad_url<'a>(tokenizer: &mut Tokenizer<'a>, start_pos: SourcePosition) -> Token<'a> {
+        // Consume up to the closing )
+        while !tokenizer.is_eof() {
+            match_byte! { tokenizer.next_byte_unchecked(),
+                b')' => {
+                    let contents = tokenizer.slice_from(start_pos).into();
+                    tokenizer.advance(1);
+                    return BadUrl(contents)
+                }
+                b'\\' => {
+                    tokenizer.advance(1);
+                    if matches!(tokenizer.next_byte(), Some(b')') | Some(b'\\')) {
+                        tokenizer.advance(1); // Skip an escaped ')' or '\'
+                    }
+                }
+                b'\n' | b'\x0C' | b'\r' => {
+                    tokenizer.consume_newline();
+                }
+                b => {
+                    tokenizer.consume_known_byte(b);
+                }
+            }
+        }
+        BadUrl(tokenizer.slice_from(start_pos).into())
+    }
+}
+
+// (value, number of digits up to 6)
+fn consume_hex_digits(tokenizer: &mut Tokenizer<'_>) -> (u32, u32) {
+    let mut value = 0;
+    let mut digits = 0;
+    while digits < 6 && !tokenizer.is_eof() {
+        match byte_to_hex_digit(tokenizer.next_byte_unchecked()) {
+            Some(digit) => {
+                value = value * 16 + digit;
+                digits += 1;
+                tokenizer.advance(1);
+            }
+            None => break,
+        }
+    }
+    (value, digits)
+}
+
+// Same constraints as consume_escape except it writes into `bytes` the result
+// instead of returning it.
+fn consume_escape_and_write(tokenizer: &mut Tokenizer, bytes: &mut Vec<u8>) {
+    bytes.extend(
+        consume_escape(tokenizer)
+            .encode_utf8(&mut [0; 4])
+            .as_bytes(),
+    )
+}
+
+// Assumes that the U+005C REVERSE SOLIDUS (\) has already been consumed
+// and that the next input character has already been verified
+// to not be a newline.
+fn consume_escape(tokenizer: &mut Tokenizer) -> char {
+    if tokenizer.is_eof() {
+        return '\u{FFFD}';
+    } // Escaped EOF
+    match_byte! { tokenizer.next_byte_unchecked(),
+        b'0'..=b'9' | b'A'..=b'F' | b'a'..=b'f' => {
+            let (c, _) = consume_hex_digits(tokenizer);
+            if !tokenizer.is_eof() {
+                match_byte! { tokenizer.next_byte_unchecked(),
+                    b' ' | b'\t' => {
+                        tokenizer.advance(1)
+                    }
+                    b'\n' | b'\x0C' | b'\r' => {
+                        tokenizer.consume_newline();
+                    }
+                    _ => {}
+                }
+            }
+            static REPLACEMENT_CHAR: char = '\u{FFFD}';
+            if c != 0 {
+                let c = char::from_u32(c);
+                c.unwrap_or(REPLACEMENT_CHAR)
+            } else {
+                REPLACEMENT_CHAR
+            }
+        },
+        b'\0' => {
+            tokenizer.advance(1);
+            '\u{FFFD}'
+        }
+        _ => tokenizer.consume_char(),
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/unicode_range.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/unicode_range.rs
new file mode 100644
index 000000000000..ce6bb3b5e7d2
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/unicode_range.rs
@@ -0,0 +1,179 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! https://drafts.csswg.org/css-syntax/#urange
+
+use crate::tokenizer::Token;
+use crate::{BasicParseError, Parser, ToCss};
+use std::char;
+use std::fmt;
+
+/// One contiguous range of code points.
+///
+/// Can not be empty. Can represent a single code point when start == end.
+#[derive(PartialEq, Eq, Clone, Hash)]
+#[repr(C)]
+pub struct UnicodeRange {
+    /// Inclusive start of the range. In [0, end].
+    pub start: u32,
+
+    /// Inclusive end of the range. In [0, 0x10FFFF].
+    pub end: u32,
+}
+
+impl UnicodeRange {
+    /// https://drafts.csswg.org/css-syntax/#urange-syntax
+    pub fn parse<'i>(input: &mut Parser<'i, '_>) -> Result<Self, BasicParseError<'i>> {
+        // <urange> =
+        //   u '+' <ident-token> '?'* |
+        //   u <dimension-token> '?'* |
+        //   u <number-token> '?'* |
+        //   u <number-token> <dimension-token> |
+        //   u <number-token> <number-token> |
+        //   u '+' '?'+
+
+        input.expect_ident_matching("u")?;
+        let after_u = input.position();
+        parse_tokens(input)?;
+
+        // This deviates from the spec in case there are CSS comments
+        // between tokens in the middle of one <unicode-range>,
+        // but oh well…
+        let concatenated_tokens = input.slice_from(after_u);
+
+        let range = match parse_concatenated(concatenated_tokens.as_bytes()) {
+            Ok(range) => range,
+            Err(()) => {
+                return Err(input
+                    .new_basic_unexpected_token_error(Token::Ident(concatenated_tokens.into())))
+            }
+        };
+        if range.end > char::MAX as u32 || range.start > range.end {
+            Err(input.new_basic_unexpected_token_error(Token::Ident(concatenated_tokens.into())))
+        } else {
+            Ok(range)
+        }
+    }
+}
+
+fn parse_tokens<'i>(input: &mut Parser<'i, '_>) -> Result<(), BasicParseError<'i>> {
+    match input.next_including_whitespace()?.clone() {
+        Token::Delim('+') => {
+            match *input.next_including_whitespace()? {
+                Token::Ident(_) => {}
+                Token::Delim('?') => {}
+                ref t => {
+                    let t = t.clone();
+                    return Err(input.new_basic_unexpected_token_error(t));
+                }
+            }
+            parse_question_marks(input)
+        }
+        Token::Dimension { .. } => parse_question_marks(input),
+        Token::Number { .. } => {
+            let after_number = input.state();
+            match input.next_including_whitespace() {
+                Ok(&Token::Delim('?')) => parse_question_marks(input),
+                Ok(&Token::Dimension { .. }) => {}
+                Ok(&Token::Number { .. }) => {}
+                _ => input.reset(&after_number),
+            }
+        }
+        t => return Err(input.new_basic_unexpected_token_error(t)),
+    }
+    Ok(())
+}
+
+/// Consume as many '?' as possible
+fn parse_question_marks(input: &mut Parser) {
+    loop {
+        let start = input.state();
+        match input.next_including_whitespace() {
+            Ok(&Token::Delim('?')) => {}
+            _ => {
+                input.reset(&start);
+                return;
+            }
+        }
+    }
+}
+
+fn parse_concatenated(text: &[u8]) -> Result<UnicodeRange, ()> {
+    let mut text = match text.split_first() {
+        Some((&b'+', text)) => text,
+        _ => return Err(()),
+    };
+    let (first_hex_value, hex_digit_count) = consume_hex(&mut text);
+    let question_marks = consume_question_marks(&mut text);
+    let consumed = hex_digit_count + question_marks;
+    if consumed == 0 || consumed > 6 {
+        return Err(());
+    }
+
+    if question_marks > 0 {
+        if text.is_empty() {
+            return Ok(UnicodeRange {
+                start: first_hex_value << (question_marks * 4),
+                end: ((first_hex_value + 1) << (question_marks * 4)) - 1,
+            });
+        }
+    } else if text.is_empty() {
+        return Ok(UnicodeRange {
+            start: first_hex_value,
+            end: first_hex_value,
+        });
+    } else if let Some((&b'-', mut text)) = text.split_first() {
+        let (second_hex_value, hex_digit_count) = consume_hex(&mut text);
+        if hex_digit_count > 0 && hex_digit_count <= 6 && text.is_empty() {
+            return Ok(UnicodeRange {
+                start: first_hex_value,
+                end: second_hex_value,
+            });
+        }
+    }
+    Err(())
+}
+
+fn consume_hex(text: &mut &[u8]) -> (u32, usize) {
+    let mut value = 0;
+    let mut digits = 0;
+    while let Some((&byte, rest)) = text.split_first() {
+        if let Some(digit_value) = (byte as char).to_digit(16) {
+            value = value * 0x10 + digit_value;
+            digits += 1;
+            *text = rest
+        } else {
+            break;
+        }
+    }
+    (value, digits)
+}
+
+fn consume_question_marks(text: &mut &[u8]) -> usize {
+    let mut question_marks = 0;
+    while let Some((&b'?', rest)) = text.split_first() {
+        question_marks += 1;
+        *text = rest
+    }
+    question_marks
+}
+
+impl fmt::Debug for UnicodeRange {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        self.to_css(formatter)
+    }
+}
+
+impl ToCss for UnicodeRange {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        write!(dest, "U+{:X}", self.start)?;
+        if self.end != self.start {
+            write!(dest, "-{:X}", self.end)?;
+        }
+        Ok(())
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo_vcs_info.json
deleted file mode 100644
index 8842a712ff0c..000000000000
--- a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo_vcs_info.json
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "git": {
-    "sha1": "65d6c3e0a5dc222f745dbc7bc16c92a49e3d2aff"
-  }
-}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs
deleted file mode 100644
index 971c03048d41..000000000000
--- a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs
+++ /dev/null
@@ -1,39 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro]
-pub fn _cssparser_internal_max_len(input: TokenStream) -> TokenStream {
-    struct Input {
-        max_length: usize,
-    }
-
-    impl syn::parse::Parse for Input {
-        fn parse(input: syn::parse::ParseStream) -> syn::parse::Result<Self> {
-            let mut max_length = 0;
-            while !input.is_empty() {
-                if input.peek(syn::Token![_]) {
-                    input.parse::<syn::Token![_]>().unwrap();
-                    continue;
-                }
-                let lit: syn::LitStr = input.parse()?;
-                let value = lit.value();
-                if value.to_ascii_lowercase() != value {
-                    return Err(syn::Error::new(lit.span(), "must be ASCII-lowercase"));
-                }
-                max_length = max_length.max(value.len());
-            }
-            Ok(Input { max_length })
-        }
-    }
-
-    let Input { max_length } = syn::parse_macro_input!(input);
-    quote::quote!(
-        pub(super) const MAX_LENGTH: usize = #max_length;
-    )
-    .into()
-}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo_vcs_info.json
new file mode 100644
index 000000000000..9408d884d6a8
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "0ebd17bcd13808f087b083f34d2f816e380b5155"
+  },
+  "path_in_vcs": "macros"
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml
similarity index 63%
rename from third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml
rename to third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml
index 38d01023a1f5..601ac6a3af67 100644
--- a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml
@@ -3,17 +3,16 @@
 # When uploading crates to the registry Cargo will automatically
 # "normalize" Cargo.toml files for maximal compatibility
 # with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g., crates.io) dependencies
+# to registry (e.g., crates.io) dependencies.
 #
-# If you believe there's an error in this file please file an
-# issue against the rust-lang/cargo repository. If you're
-# editing this file be aware that the upstream Cargo.toml
-# will likely look very different (and much more reasonable)
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
 
 [package]
 edition = "2018"
 name = "cssparser-macros"
-version = "0.6.0"
+version = "0.6.1"
 authors = ["Simon Sapin <simon.sapin@exyr.org>"]
 description = "Procedural macros for cssparser"
 documentation = "https://docs.rs/cssparser-macros/"
@@ -23,9 +22,13 @@ repository = "https://github.com/servo/rust-cssparser"
 [lib]
 path = "lib.rs"
 proc-macro = true
+
 [dependencies.quote]
 version = "1"
 
 [dependencies.syn]
-version = "1"
-features = ["full", "extra-traits"]
+version = "2"
+features = [
+    "full",
+    "extra-traits",
+]
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml.orig
similarity index 81%
rename from third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml.orig
rename to third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml.orig
index 3f834e5e7c54..1c225bf24633 100644
--- a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/Cargo.toml.orig
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/Cargo.toml.orig
@@ -1,6 +1,6 @@
 [package]
 name = "cssparser-macros"
-version = "0.6.0"
+version = "0.6.1"
 authors = ["Simon Sapin <simon.sapin@exyr.org>"]
 description = "Procedural macros for cssparser"
 documentation = "https://docs.rs/cssparser-macros/"
@@ -14,4 +14,4 @@ proc-macro = true
 
 [dependencies]
 quote = "1"
-syn = {version = "1", features = ["full", "extra-traits"]}
+syn = {version = "2", features = ["full", "extra-traits"]}
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/LICENSE b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/LICENSE
new file mode 100644
index 000000000000..14e2f777f6c3
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/LICENSE
@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in 
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.
diff --git a/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs
new file mode 100644
index 000000000000..4354cc8e7cb6
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs
@@ -0,0 +1,190 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn _cssparser_internal_max_len(input: TokenStream) -> TokenStream {
+    struct Input {
+        max_length: usize,
+    }
+
+    impl syn::parse::Parse for Input {
+        fn parse(input: syn::parse::ParseStream) -> syn::parse::Result<Self> {
+            let mut max_length = 0;
+            while !input.is_empty() {
+                if input.peek(syn::Token![_]) {
+                    input.parse::<syn::Token![_]>().unwrap();
+                    continue;
+                }
+                let lit: syn::LitStr = input.parse()?;
+                let value = lit.value();
+                if value.to_ascii_lowercase() != value {
+                    return Err(syn::Error::new(lit.span(), "must be ASCII-lowercase"));
+                }
+                max_length = max_length.max(value.len());
+            }
+            Ok(Input { max_length })
+        }
+    }
+
+    let Input { max_length } = syn::parse_macro_input!(input);
+    quote::quote!(
+        pub(super) const MAX_LENGTH: usize = #max_length;
+    )
+    .into()
+}
+
+fn get_byte_from_lit(lit: &syn::Lit) -> u8 {
+    if let syn::Lit::Byte(ref byte) = *lit {
+        byte.value()
+    } else {
+        panic!("Found a pattern that wasn't a byte")
+    }
+}
+
+fn get_byte_from_expr_lit(expr: &syn::Expr) -> u8 {
+    match *expr {
+        syn::Expr::Lit(syn::ExprLit { ref lit, .. }) => {
+            get_byte_from_lit(lit)
+        }
+        _ => unreachable!(),
+    }
+}
+
+/// Parse a pattern and fill the table accordingly
+fn parse_pat_to_table<'a>(
+    pat: &'a syn::Pat,
+    case_id: u8,
+    wildcard: &mut Option<&'a syn::Ident>,
+    table: &mut [u8; 256],
+) {
+    match pat {
+        &syn::Pat::Lit(syn::PatLit { ref lit, .. }) => {
+            let value = get_byte_from_lit(lit);
+            if table[value as usize] == 0 {
+                table[value as usize] = case_id;
+            }
+        }
+        &syn::Pat::Range(syn::PatRange { ref start, ref end, .. }) => {
+            let lo = get_byte_from_expr_lit(&start.as_ref().unwrap());
+            let hi = get_byte_from_expr_lit(&end.as_ref().unwrap());
+            for value in lo..hi {
+                if table[value as usize] == 0 {
+                    table[value as usize] = case_id;
+                }
+            }
+            if table[hi as usize] == 0 {
+                table[hi as usize] = case_id;
+            }
+        }
+        &syn::Pat::Wild(_) => {
+            for byte in table.iter_mut() {
+                if *byte == 0 {
+                    *byte = case_id;
+                }
+            }
+        }
+        &syn::Pat::Ident(syn::PatIdent { ref ident, .. }) => {
+            assert_eq!(*wildcard, None);
+            *wildcard = Some(ident);
+            for byte in table.iter_mut() {
+                if *byte == 0 {
+                    *byte = case_id;
+                }
+            }
+        }
+        &syn::Pat::Or(syn::PatOr { ref cases, .. }) => {
+            for case in cases {
+                parse_pat_to_table(case, case_id, wildcard, table);
+            }
+        }
+        _ => {
+            panic!("Unexpected pattern: {:?}. Buggy code ?", pat);
+        }
+    }
+}
+
+/// Expand a TokenStream corresponding to the `match_byte` macro.
+///
+/// ## Example
+///
+/// ```rust
+/// match_byte! { tokenizer.next_byte_unchecked(),
+///     b'a'..b'z' => { ... }
+///     b'0'..b'9' => { ... }
+///     b'\n' | b'\\' => { ... }
+///     foo => { ... }
+///  }
+///  ```
+///
+#[proc_macro]
+pub fn match_byte(input: TokenStream) -> TokenStream {
+    use syn::spanned::Spanned;
+    struct MatchByte {
+        expr: syn::Expr,
+        arms: Vec<syn::Arm>,
+    }
+
+    impl syn::parse::Parse for MatchByte {
+        fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+            Ok(MatchByte {
+                expr: {
+                    let expr = input.parse()?;
+                    input.parse::<syn::Token![,]>()?;
+                    expr
+                },
+                arms: {
+                    let mut arms = Vec::new();
+                    while !input.is_empty() {
+                        let arm = input.call(syn::Arm::parse)?;
+                        assert!(arm.guard.is_none(), "match_byte doesn't support guards");
+                        assert!(
+                            arm.attrs.is_empty(),
+                            "match_byte doesn't support attributes"
+                        );
+                        arms.push(arm);
+                    }
+                    arms
+                },
+            })
+        }
+    }
+    let MatchByte { expr, arms } = syn::parse_macro_input!(input);
+
+    let mut cases = Vec::new();
+    let mut table = [0u8; 256];
+    let mut match_body = Vec::new();
+    let mut wildcard = None;
+    for (i, ref arm) in arms.iter().enumerate() {
+        let case_id = i + 1;
+        let index = case_id as isize;
+        let name = syn::Ident::new(&format!("Case{}", case_id), arm.span());
+        let pat = &arm.pat;
+        parse_pat_to_table(pat, case_id as u8, &mut wildcard, &mut table);
+
+        cases.push(quote::quote!(#name = #index));
+        let body = &arm.body;
+        match_body.push(quote::quote!(Case::#name => { #body }))
+    }
+
+    let en = quote::quote!(enum Case {
+        #(#cases),*
+    });
+
+    let mut table_content = Vec::new();
+    for entry in table.iter() {
+        let name: syn::Path = syn::parse_str(&format!("Case::Case{}", entry)).unwrap();
+        table_content.push(name);
+    }
+    let table = quote::quote!(static __CASES: [Case; 256] = [#(#table_content),*];);
+
+    if let Some(binding) = wildcard {
+        quote::quote!({ #en #table let #binding = #expr; match __CASES[#binding as usize] { #(#match_body),* }})
+    } else {
+        quote::quote!({ #en #table match __CASES[#expr as usize] { #(#match_body),* }})
+    }.into()
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo_vcs_info.json
new file mode 100644
index 000000000000..01741282defd
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "a38b9c42cbf06049b2cc1859bfbf9d5895e4b018"
+  },
+  "path_in_vcs": ""
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/dependabot.yml b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/dependabot.yml
new file mode 100644
index 000000000000..de79e0fcb416
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/dependabot.yml
@@ -0,0 +1,11 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/workflows/test.yml b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/workflows/test.yml
new file mode 100644
index 000000000000..1d5a6d32d793
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.github/workflows/test.yml
@@ -0,0 +1,47 @@
+name: Tests
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "master"
+
+jobs:
+  format:
+    name: Format code
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+            components: rustfmt
+      - run: cargo fmt -- --check
+
+  clippy:
+    name: Clippy check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+            components: clippy
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo clippy --all-targets --all-features -- --deny warnings
+
+  test:
+    name: Test code
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust_version: [stable, beta, nightly]
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@master
+        with:
+            toolchain: ${{matrix.rust_version}}
+      - uses: Swatinem/rust-cache@v2
+        with:
+            key: ${{matrix.rust_version}}
+      - run: cargo update
+      - run: cargo test --all-features
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.gitignore b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.gitignore
new file mode 100644
index 000000000000..5b99a65f2b38
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/.gitignore
@@ -0,0 +1,4 @@
+target
+Cargo.lock
+.vscode
+.idea
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml
new file mode 100644
index 000000000000..38c0d85f2fa3
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml
@@ -0,0 +1,87 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "ego-tree"
+version = "0.10.0"
+authors = [
+    "June McEnroe <june@causal.agency>",
+    "Carlo Federico Vescovo <vescovocarlofederico@gmail.com>",
+]
+build = false
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "Vec-backed ID-tree"
+readme = "README.md"
+keywords = [
+    "tree",
+    "vec",
+    "id",
+    "index",
+]
+license = "ISC"
+repository = "https://github.com/rust-scraper/ego-tree"
+
+[lib]
+name = "ego_tree"
+path = "src/lib.rs"
+
+[[example]]
+name = "simple_tree"
+path = "examples/simple_tree.rs"
+
+[[test]]
+name = "iter"
+path = "tests/iter.rs"
+
+[[test]]
+name = "macro"
+path = "tests/macro.rs"
+
+[[test]]
+name = "node_mut"
+path = "tests/node_mut.rs"
+
+[[test]]
+name = "node_ref"
+path = "tests/node_ref.rs"
+
+[[test]]
+name = "serde"
+path = "tests/serde.rs"
+
+[[test]]
+name = "sort"
+path = "tests/sort.rs"
+
+[[test]]
+name = "subtree"
+path = "tests/subtree.rs"
+
+[[test]]
+name = "tree"
+path = "tests/tree.rs"
+
+[dependencies.serde]
+version = "1.0.209"
+optional = true
+
+[dev-dependencies.serde]
+version = "1.0.209"
+
+[dev-dependencies.serde_test]
+version = "1.0.177"
+
+[features]
+serde = ["dep:serde"]
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml.orig
new file mode 100644
index 000000000000..c1c1c846cc6a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/Cargo.toml.orig
@@ -0,0 +1,23 @@
+[package]
+name = "ego-tree"
+edition = "2021"
+version = "0.10.0"
+description = "Vec-backed ID-tree"
+keywords = ["tree", "vec", "id", "index"]
+authors = [
+    "June McEnroe <june@causal.agency>",
+    "Carlo Federico Vescovo <vescovocarlofederico@gmail.com>",
+]
+license = "ISC"
+repository = "https://github.com/rust-scraper/ego-tree"
+readme = "README.md"
+
+[features]
+serde = ["dep:serde"]
+
+[dependencies]
+serde = { version = "1.0.209", optional = true }
+
+[dev-dependencies]
+serde = "1.0.209"
+serde_test = "1.0.177"
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/LICENSE b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/LICENSE
new file mode 100644
index 000000000000..27c7cb37a632
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/LICENSE
@@ -0,0 +1,13 @@
+Copyright © 2016, June McEnroe <june@causal.agency>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/README.md b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/README.md
new file mode 100644
index 000000000000..df822a9440ad
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/README.md
@@ -0,0 +1,123 @@
+# Ego Tree
+
+[![crates.io](https://img.shields.io/crates/v/ego-tree?color=dark-green)][crate]
+[![downloads](https://img.shields.io/crates/d/ego-tree)][crate]
+[![test](https://github.com/rust-scraper/ego-tree/actions/workflows/test.yml/badge.svg)][tests]
+
+`ego-tree` is a Rust crate that provides a Vec-backed ID-tree implementation. It offers a flexible and efficient way to create and manipulate tree structures in Rust, with a focus on performance and ease of use.
+
+`ego-tree` is on [Crates.io][crate] and [GitHub][github].
+
+## Design Philosophy
+
+The design of `ego-tree` is centered around the following principles:
+
+1. **Efficiency**: The tree structure is backed by a Vec, allowing for fast, cache-friendly operations and efficient memory usage.
+
+2. **Flexibility**: Nodes can have any number of children, allowing for the representation of various tree structures.
+
+3. **Stability**: Node references remain valid even after modifying the tree structure, thanks to the use of stable NodeId indices.
+
+4. **Safety**: The API is designed to prevent common errors, such as creating cycles or detaching the root node.
+
+5. **Ergonomics**: The crate provides both low-level operations and high-level conveniences like the `tree!` macro for easy tree construction.
+
+## Key Design Choices
+
+### Vec-Backed Structure
+
+Unlike traditional pointer-based trees, `ego-tree` uses a Vec to store all nodes. This design choice offers several advantages:
+
+- Improved cache locality, potentially leading to better performance
+- Simplified memory management
+- Easier serialization and deserialization
+- Constant-time access to any node by its ID
+
+### Node IDs
+
+Nodes are identified by `NodeId`s, which are wrappers around indices into the underlying Vec. This approach allows for:
+
+- Stable references to nodes, even as the tree structure changes
+- Efficient node lookup (O(1) time complexity)
+- Compact representation of relationships between nodes
+
+### Immutable and Mutable Node References
+
+The crate provides both `NodeRef` (immutable) and `NodeMut` (mutable) types for working with nodes. This separation allows for:
+
+- Clear distinction between read-only and modifying operations
+- Prevention of multiple mutable references to the same node, enforcing Rust's borrowing rules
+- Efficient implementation of various tree traversal iterators
+
+### Orphan Nodes
+
+Nodes can be detached from the tree but not removed entirely. This design choice:
+
+- Simplifies certain tree manipulation algorithms
+- Allows for temporary detachment and reattachment of subtrees
+- Maintains the validity of NodeIds, even for detached nodes
+
+### Rich Iterator Support
+
+The crate provides a variety of iterator types for traversing the tree in different ways. This design:
+
+- Allows for efficient and idiomatic tree traversal
+- Supports various algorithms and use cases without sacrificing performance
+- Leverages Rust's powerful iterator ecosystem
+
+## Use Cases
+
+`ego-tree` is well-suited for applications that require:
+
+- Efficient representation and manipulation of hierarchical data structures
+- Frequent traversal and modification of tree structures
+- Stable references to tree nodes across operations
+- Serialization and deserialization of tree structures
+
+Some potential use cases include:
+
+- DOM-like structures for document processing
+- File system representations
+- Organizational hierarchies
+- Game scene graphs
+- Abstract syntax trees for compilers or interpreters
+
+## Getting Started
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+ego-tree = "0.6.2"
+```
+
+Basic usage:
+
+```rust
+use ego_tree::Tree;
+
+let mut tree = Tree::new(1);
+let mut root = tree.root_mut();
+root.append(2);
+let mut child = root.append(3);
+child.append(4);
+child.append(5);
+```
+
+For more detailed usage examples and API documentation, please refer to the [documentation](https://docs.rs/ego-tree).
+
+## License
+
+This project is licensed under the ISC License.
+
+## Contributing
+
+Contributions are welcome! Please feel free to submit a Pull Request.
+
+## Credits
+
+`ego-tree` is created and maintained by the team of [rust-scraper](https://github.com/rust-scraper).
+
+[crate]: https://crates.io/crates/ego-tree
+[github]: https://github.com/rust-scraper/ego-tree
+[tests]: https://github.com/rust-scraper/ego-tree/actions/workflows/test.yml
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/examples/simple_tree.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/examples/simple_tree.rs
new file mode 100644
index 000000000000..f2c5b8235586
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/examples/simple_tree.rs
@@ -0,0 +1,28 @@
+//! Implements this tree
+//! ```
+//! 1
+//! ├── 2
+//! └── 3
+//!     ├── 4
+//!     └── 5
+//! ```
+
+use ego_tree::{tree, NodeMut, Tree};
+
+fn main() {
+    // Manual construction of the tree
+    let mut tree: Tree<i32> = Tree::new(1);
+    let mut root: NodeMut<i32> = tree.root_mut();
+    root.append(2);
+    let mut child: NodeMut<i32> = root.append(3);
+    child.append(4);
+    child.append(5);
+    println!("Manual:\n{tree}");
+
+    // Construction of the tree through the tree! macro
+    let macro_tree: Tree<i32> = tree!(1 => {2, 3 => {4, 5}});
+    println!("Automated:\n{macro_tree}");
+
+    // Prooving equality
+    assert_eq!(tree, macro_tree);
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/display.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/display.rs
new file mode 100644
index 000000000000..5744f39160b9
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/display.rs
@@ -0,0 +1,89 @@
+use std::fmt::Display;
+
+/// Indentation token
+#[derive(Debug)]
+struct Token {
+    /// Is followed by a brother
+    siblings: bool,
+    /// Is intermediate while printing children
+    children: bool,
+}
+
+impl Display for Token {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let Token { siblings, children } = self;
+
+        write!(
+            f,
+            "{}",
+            match (siblings, children) {
+                (true, true) => "│   ",
+                (true, false) => "├── ",
+                (false, true) => "    ",
+                (false, false) => "└── ",
+            }
+        )
+    }
+}
+
+impl Token {
+    /// Create a new indentation token
+    fn new(siblings: bool) -> Self {
+        Token {
+            siblings,
+            children: false,
+        }
+    }
+
+    /// Set children flag before starting displaying children
+    fn set_children(&mut self) {
+        self.children = true;
+    }
+}
+
+/// Manages the state during the display operation
+#[derive(Debug)]
+pub struct Indentation {
+    tokens: Vec<Token>,
+    ignore_root: bool,
+}
+
+impl Display for Indentation {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let first: usize = if self.ignore_root { 1 } else { 0 };
+
+        for token in &self.tokens[first..] {
+            write!(f, "{token}")?;
+        }
+
+        Ok(())
+    }
+}
+
+impl Indentation {
+    /// Creates a new indentation handler
+    pub fn new(ignore_root: bool) -> Self {
+        Indentation {
+            tokens: Vec::new(),
+            ignore_root,
+        }
+    }
+
+    /// Adds a new layer of indentation
+    pub fn indent(&mut self, siblings: bool) -> &mut Self {
+        // Setup children mode for previous tokens
+        let len = self.tokens.len();
+        if len > 0 {
+            self.tokens[len - 1].set_children();
+        }
+
+        self.tokens.push(Token::new(siblings));
+        self
+    }
+
+    /// Removes the last layer of indentation
+    pub fn deindent(&mut self) -> &mut Self {
+        self.tokens.pop();
+        self
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/iter.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/iter.rs
new file mode 100644
index 000000000000..a40777c70070
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/iter.rs
@@ -0,0 +1,356 @@
+use std::iter::FusedIterator;
+use std::ops::Range;
+use std::{slice, vec};
+
+use crate::{Node, NodeId, NodeRef, Tree};
+
+/// Iterator that moves out of a tree in insert order.
+#[derive(Debug)]
+pub struct IntoIter<T>(vec::IntoIter<Node<T>>);
+impl<T> ExactSizeIterator for IntoIter<T> {}
+impl<T> FusedIterator for IntoIter<T> {}
+impl<T> Iterator for IntoIter<T> {
+    type Item = T;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next().map(|node| node.value)
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.0.size_hint()
+    }
+}
+impl<T> DoubleEndedIterator for IntoIter<T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back().map(|node| node.value)
+    }
+}
+
+/// Iterator over values in insert order.
+#[derive(Debug)]
+pub struct Values<'a, T: 'a>(slice::Iter<'a, Node<T>>);
+impl<'a, T: 'a> Clone for Values<'a, T> {
+    fn clone(&self) -> Self {
+        Values(self.0.clone())
+    }
+}
+impl<'a, T: 'a> ExactSizeIterator for Values<'a, T> {}
+impl<'a, T: 'a> FusedIterator for Values<'a, T> {}
+impl<'a, T: 'a> Iterator for Values<'a, T> {
+    type Item = &'a T;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next().map(|node| &node.value)
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.0.size_hint()
+    }
+}
+impl<'a, T: 'a> DoubleEndedIterator for Values<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back().map(|node| &node.value)
+    }
+}
+
+/// Mutable iterator over values in insert order.
+#[derive(Debug)]
+pub struct ValuesMut<'a, T: 'a>(slice::IterMut<'a, Node<T>>);
+impl<'a, T: 'a> ExactSizeIterator for ValuesMut<'a, T> {}
+impl<'a, T: 'a> FusedIterator for ValuesMut<'a, T> {}
+impl<'a, T: 'a> Iterator for ValuesMut<'a, T> {
+    type Item = &'a mut T;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next().map(|node| &mut node.value)
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.0.size_hint()
+    }
+}
+impl<'a, T: 'a> DoubleEndedIterator for ValuesMut<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back().map(|node| &mut node.value)
+    }
+}
+
+/// Iterator over nodes in insert order.
+#[derive(Debug)]
+pub struct Nodes<'a, T: 'a> {
+    tree: &'a Tree<T>,
+    iter: Range<usize>,
+}
+impl<'a, T: 'a> Clone for Nodes<'a, T> {
+    fn clone(&self) -> Self {
+        Self {
+            tree: self.tree,
+            iter: self.iter.clone(),
+        }
+    }
+}
+impl<'a, T: 'a> ExactSizeIterator for Nodes<'a, T> {}
+impl<'a, T: 'a> FusedIterator for Nodes<'a, T> {}
+impl<'a, T: 'a> Iterator for Nodes<'a, T> {
+    type Item = NodeRef<'a, T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter
+            .next()
+            .map(|i| unsafe { self.tree.get_unchecked(NodeId::from_index(i)) })
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+impl<'a, T: 'a> DoubleEndedIterator for Nodes<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.iter
+            .next_back()
+            .map(|i| unsafe { self.tree.get_unchecked(NodeId::from_index(i)) })
+    }
+}
+
+impl<T> IntoIterator for Tree<T> {
+    type Item = T;
+    type IntoIter = IntoIter<T>;
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter(self.vec.into_iter())
+    }
+}
+
+impl<T> Tree<T> {
+    /// Returns an iterator over values in insert order.
+    pub fn values(&self) -> Values<T> {
+        Values(self.vec.iter())
+    }
+
+    /// Returns a mutable iterator over values in insert order.
+    pub fn values_mut(&mut self) -> ValuesMut<T> {
+        ValuesMut(self.vec.iter_mut())
+    }
+
+    /// Returns an iterator over nodes in insert order.
+    pub fn nodes(&self) -> Nodes<T> {
+        Nodes {
+            tree: self,
+            iter: 0..self.vec.len(),
+        }
+    }
+}
+
+macro_rules! axis_iterators {
+    ($(#[$m:meta] $i:ident($f:path);)*) => {
+        $(
+            #[$m]
+            #[derive(Debug)]
+            pub struct $i<'a, T: 'a>(Option<NodeRef<'a, T>>);
+            impl<'a, T: 'a> Clone for $i<'a, T> {
+                fn clone(&self) -> Self {
+                    $i(self.0)
+                }
+            }
+            impl<'a, T: 'a> FusedIterator for $i<'a, T> {}
+            impl<'a, T: 'a> Iterator for $i<'a, T> {
+                type Item = NodeRef<'a, T>;
+                fn next(&mut self) -> Option<Self::Item> {
+                    let node = self.0.take();
+                    self.0 = node.as_ref().and_then($f);
+                    node
+                }
+            }
+        )*
+    };
+}
+
+axis_iterators! {
+    /// Iterator over ancestors.
+    Ancestors(NodeRef::parent);
+
+    /// Iterator over previous siblings.
+    PrevSiblings(NodeRef::prev_sibling);
+
+    /// Iterator over next siblings.
+    NextSiblings(NodeRef::next_sibling);
+
+    /// Iterator over first children.
+    FirstChildren(NodeRef::first_child);
+
+    /// Iterator over last children.
+    LastChildren(NodeRef::last_child);
+}
+
+/// Iterator over children.
+#[derive(Debug)]
+pub struct Children<'a, T: 'a> {
+    front: Option<NodeRef<'a, T>>,
+    back: Option<NodeRef<'a, T>>,
+}
+impl<'a, T: 'a> Clone for Children<'a, T> {
+    fn clone(&self) -> Self {
+        Self {
+            front: self.front,
+            back: self.back,
+        }
+    }
+}
+impl<'a, T: 'a> FusedIterator for Children<'a, T> {}
+impl<'a, T: 'a> Iterator for Children<'a, T> {
+    type Item = NodeRef<'a, T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.front == self.back {
+            let node = self.front.take();
+            self.back = None;
+            node
+        } else {
+            let node = self.front.take();
+            self.front = node.as_ref().and_then(NodeRef::next_sibling);
+            node
+        }
+    }
+}
+impl<'a, T: 'a> DoubleEndedIterator for Children<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        if self.back == self.front {
+            let node = self.back.take();
+            self.front = None;
+            node
+        } else {
+            let node = self.back.take();
+            self.back = node.as_ref().and_then(NodeRef::prev_sibling);
+            node
+        }
+    }
+}
+
+/// Open or close edge of a node.
+#[derive(Debug)]
+pub enum Edge<'a, T: 'a> {
+    /// Open.
+    Open(NodeRef<'a, T>),
+    /// Close.
+    Close(NodeRef<'a, T>),
+}
+impl<'a, T: 'a> Copy for Edge<'a, T> {}
+impl<'a, T: 'a> Clone for Edge<'a, T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl<'a, T: 'a> Eq for Edge<'a, T> {}
+impl<'a, T: 'a> PartialEq for Edge<'a, T> {
+    fn eq(&self, other: &Self) -> bool {
+        match (*self, *other) {
+            (Edge::Open(a), Edge::Open(b)) | (Edge::Close(a), Edge::Close(b)) => a == b,
+            _ => false,
+        }
+    }
+}
+
+/// Iterator which traverses a subtree.
+#[derive(Debug)]
+pub struct Traverse<'a, T: 'a> {
+    root: Option<NodeRef<'a, T>>,
+    edge: Option<Edge<'a, T>>,
+}
+impl<'a, T: 'a> Clone for Traverse<'a, T> {
+    fn clone(&self) -> Self {
+        Self {
+            root: self.root,
+            edge: self.edge,
+        }
+    }
+}
+impl<'a, T: 'a> FusedIterator for Traverse<'a, T> {}
+impl<'a, T: 'a> Iterator for Traverse<'a, T> {
+    type Item = Edge<'a, T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.edge {
+            None => {
+                if let Some(root) = self.root {
+                    self.edge = Some(Edge::Open(root));
+                }
+            }
+            Some(Edge::Open(node)) => {
+                if let Some(first_child) = node.first_child() {
+                    self.edge = Some(Edge::Open(first_child));
+                } else {
+                    self.edge = Some(Edge::Close(node));
+                }
+            }
+            Some(Edge::Close(node)) => {
+                if node == self.root.unwrap() {
+                    self.root = None;
+                    self.edge = None;
+                } else if let Some(next_sibling) = node.next_sibling() {
+                    self.edge = Some(Edge::Open(next_sibling));
+                } else {
+                    self.edge = node.parent().map(Edge::Close);
+                }
+            }
+        }
+        self.edge
+    }
+}
+
+/// Iterator over a node and its descendants.
+#[derive(Debug)]
+pub struct Descendants<'a, T: 'a>(Traverse<'a, T>);
+impl<'a, T: 'a> Clone for Descendants<'a, T> {
+    fn clone(&self) -> Self {
+        Descendants(self.0.clone())
+    }
+}
+impl<'a, T: 'a> FusedIterator for Descendants<'a, T> {}
+impl<'a, T: 'a> Iterator for Descendants<'a, T> {
+    type Item = NodeRef<'a, T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        for edge in &mut self.0 {
+            if let Edge::Open(node) = edge {
+                return Some(node);
+            }
+        }
+        None
+    }
+}
+
+impl<'a, T: 'a> NodeRef<'a, T> {
+    /// Returns an iterator over ancestors.
+    pub fn ancestors(&self) -> Ancestors<'a, T> {
+        Ancestors(self.parent())
+    }
+
+    /// Returns an iterator over previous siblings.
+    pub fn prev_siblings(&self) -> PrevSiblings<'a, T> {
+        PrevSiblings(self.prev_sibling())
+    }
+
+    /// Returns an iterator over next siblings.
+    pub fn next_siblings(&self) -> NextSiblings<'a, T> {
+        NextSiblings(self.next_sibling())
+    }
+
+    /// Returns an iterator over first children.
+    pub fn first_children(&self) -> FirstChildren<'a, T> {
+        FirstChildren(self.first_child())
+    }
+
+    /// Returns an iterator over last children.
+    pub fn last_children(&self) -> LastChildren<'a, T> {
+        LastChildren(self.last_child())
+    }
+
+    /// Returns an iterator over children.
+    pub fn children(&self) -> Children<'a, T> {
+        Children {
+            front: self.first_child(),
+            back: self.last_child(),
+        }
+    }
+
+    /// Returns an iterator which traverses the subtree starting at this node.
+    pub fn traverse(&self) -> Traverse<'a, T> {
+        Traverse {
+            root: Some(*self),
+            edge: None,
+        }
+    }
+
+    /// Returns an iterator over this node and its descendants.
+    pub fn descendants(&self) -> Descendants<'a, T> {
+        Descendants(self.traverse())
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs
new file mode 100644
index 000000000000..6142ca9e1e61
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs
@@ -0,0 +1,939 @@
+//! Vec-backed ID-tree.
+//!
+//! # Behavior
+//!
+//! - Trees have at least a root node;
+//! - Nodes have zero or more ordered children;
+//! - Nodes have at most one parent;
+//! - Nodes can be detached (orphaned) but not removed;
+//! - Node parent, next sibling, previous sibling, first child and last child
+//!   can be accessed in constant time;
+//! - All methods perform in constant time;
+//! - All iterators perform in linear time.
+//!
+//! # Examples
+//!
+//! ```
+//! let mut tree = ego_tree::Tree::new('a');
+//! let mut root = tree.root_mut();
+//! root.append('b');
+//! let mut c = root.append('c');
+//! c.append('d');
+//! c.append('e');
+//! ```
+//!
+//! ```
+//! #[macro_use] extern crate ego_tree;
+//! # fn main() {
+//! let tree = tree!('a' => { 'b', 'c' => { 'd', 'e' } });
+//! # }
+//! ```
+
+#![warn(
+    missing_docs,
+    missing_debug_implementations,
+    missing_copy_implementations
+)]
+
+use std::fmt::{self, Debug, Display, Formatter};
+use std::num::NonZeroUsize;
+
+#[cfg(feature = "serde")]
+pub mod serde;
+
+/// Vec-backed ID-tree.
+///
+/// Always contains at least a root node.
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct Tree<T> {
+    vec: Vec<Node<T>>,
+}
+
+/// Node ID.
+///
+/// Index into a `Tree`-internal `Vec`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct NodeId(NonZeroUsize);
+
+impl NodeId {
+    // Safety: `n` must not equal `usize::MAX`.
+    // (This is never the case for `Vec::len()`, that would mean it owns
+    // the entire address space without leaving space even for its pointer.)
+    unsafe fn from_index(n: usize) -> Self {
+        NodeId(NonZeroUsize::new_unchecked(n + 1))
+    }
+
+    fn to_index(self) -> usize {
+        self.0.get() - 1
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+struct Node<T> {
+    parent: Option<NodeId>,
+    prev_sibling: Option<NodeId>,
+    next_sibling: Option<NodeId>,
+    children: Option<(NodeId, NodeId)>,
+    value: T,
+}
+
+fn _static_assert_size_of_node() {
+    // "Instantiating" the generic `transmute` function without calling it
+    // still triggers the magic compile-time check
+    // that input and output types have the same `size_of()`.
+    let _ = std::mem::transmute::<Node<()>, [usize; 5]>;
+}
+
+impl<T> Node<T> {
+    fn new(value: T) -> Self {
+        Node {
+            parent: None,
+            prev_sibling: None,
+            next_sibling: None,
+            children: None,
+            value,
+        }
+    }
+
+    pub fn map<F, U>(self, mut transform: F) -> Node<U>
+    where
+        F: FnMut(T) -> U,
+    {
+        Node {
+            parent: self.parent,
+            prev_sibling: self.prev_sibling,
+            next_sibling: self.next_sibling,
+            children: self.children,
+            value: transform(self.value),
+        }
+    }
+
+    pub fn map_ref<F, U>(&self, mut transform: F) -> Node<U>
+    where
+        F: FnMut(&T) -> U,
+    {
+        Node {
+            parent: self.parent,
+            prev_sibling: self.prev_sibling,
+            next_sibling: self.next_sibling,
+            children: self.children,
+            value: transform(&self.value),
+        }
+    }
+}
+
+/// Node reference.
+#[derive(Debug)]
+pub struct NodeRef<'a, T: 'a> {
+    /// Node ID.
+    id: NodeId,
+
+    /// Tree containing the node.
+    tree: &'a Tree<T>,
+
+    node: &'a Node<T>,
+}
+
+/// Node mutator.
+#[derive(Debug)]
+pub struct NodeMut<'a, T: 'a> {
+    /// Node ID.
+    id: NodeId,
+
+    /// Tree containing the node.
+    tree: &'a mut Tree<T>,
+}
+
+// Trait implementations regardless of T.
+
+impl<'a, T: 'a> Copy for NodeRef<'a, T> {}
+impl<'a, T: 'a> Clone for NodeRef<'a, T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<'a, T: 'a> Eq for NodeRef<'a, T> {}
+impl<'a, T: 'a> PartialEq for NodeRef<'a, T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.id == other.id
+            && std::ptr::eq(self.tree, other.tree)
+            && std::ptr::eq(self.node, other.node)
+    }
+}
+
+impl<T> Tree<T> {
+    /// Creates a tree with a root node.
+    pub fn new(root: T) -> Self {
+        Tree {
+            vec: vec![Node::new(root)],
+        }
+    }
+
+    /// Creates a tree with a root node and the specified capacity.
+    pub fn with_capacity(root: T, capacity: usize) -> Self {
+        let mut vec = Vec::with_capacity(capacity);
+        vec.push(Node::new(root));
+        Tree { vec }
+    }
+
+    /// Returns a reference to the specified node.
+    pub fn get(&self, id: NodeId) -> Option<NodeRef<T>> {
+        self.vec.get(id.to_index()).map(|node| NodeRef {
+            id,
+            node,
+            tree: self,
+        })
+    }
+
+    /// Returns a mutator of the specified node.
+    pub fn get_mut(&mut self, id: NodeId) -> Option<NodeMut<T>> {
+        let exists = self.vec.get(id.to_index()).map(|_| ());
+        exists.map(move |_| NodeMut { id, tree: self })
+    }
+
+    unsafe fn node(&self, id: NodeId) -> &Node<T> {
+        self.vec.get_unchecked(id.to_index())
+    }
+
+    unsafe fn node_mut(&mut self, id: NodeId) -> &mut Node<T> {
+        self.vec.get_unchecked_mut(id.to_index())
+    }
+
+    /// Returns a reference to the specified node.
+    /// # Safety
+    /// The caller must ensure that `id` is a valid node ID.
+    pub unsafe fn get_unchecked(&self, id: NodeId) -> NodeRef<T> {
+        NodeRef {
+            id,
+            node: self.node(id),
+            tree: self,
+        }
+    }
+
+    /// Returns a mutator of the specified node.
+    /// # Safety
+    /// The caller must ensure that `id` is a valid node ID.
+    pub unsafe fn get_unchecked_mut(&mut self, id: NodeId) -> NodeMut<T> {
+        NodeMut { id, tree: self }
+    }
+
+    /// Returns a reference to the root node.
+    pub fn root(&self) -> NodeRef<T> {
+        unsafe { self.get_unchecked(NodeId::from_index(0)) }
+    }
+
+    /// Returns a mutator of the root node.
+    pub fn root_mut(&mut self) -> NodeMut<T> {
+        unsafe { self.get_unchecked_mut(NodeId::from_index(0)) }
+    }
+
+    /// Creates an orphan node.
+    pub fn orphan(&mut self, value: T) -> NodeMut<T> {
+        let id = unsafe { NodeId::from_index(self.vec.len()) };
+        self.vec.push(Node::new(value));
+        unsafe { self.get_unchecked_mut(id) }
+    }
+
+    /// Merge with another tree as orphan, returning the new root of tree being merged.
+    // Allowing this for compactness.
+    #[allow(clippy::option_map_unit_fn)]
+    pub fn extend_tree(&mut self, mut other_tree: Tree<T>) -> NodeMut<T> {
+        let offset = self.vec.len();
+        let offset_id = |id: NodeId| -> NodeId {
+            let old_index = id.to_index();
+            let new_index = old_index + offset;
+            unsafe { NodeId::from_index(new_index) }
+        };
+        let other_tree_root_id = offset_id(other_tree.root().id);
+        for node in other_tree.vec.iter_mut() {
+            node.parent.as_mut().map(|id| *id = offset_id(*id));
+            node.prev_sibling.as_mut().map(|id| *id = offset_id(*id));
+            node.next_sibling.as_mut().map(|id| *id = offset_id(*id));
+            node.children.as_mut().map(|(id1, id2)| {
+                *id1 = offset_id(*id1);
+                *id2 = offset_id(*id2);
+            });
+        }
+        self.vec.extend(other_tree.vec);
+        unsafe { self.get_unchecked_mut(other_tree_root_id) }
+    }
+
+    /// Maps a `Tree<T>` to `Tree<U>` by applying a function to all node values,
+    /// copying over the tree's structure and node ids untouched, consuming `self`.
+    pub fn map<F, U>(self, mut transform: F) -> Tree<U>
+    where
+        F: FnMut(T) -> U,
+    {
+        Tree {
+            vec: self
+                .vec
+                .into_iter()
+                .map(|node| node.map(&mut transform))
+                .collect(),
+        }
+    }
+
+    /// Maps a `&Tree<T>` to `Tree<U>` by applying a function to all node values,
+    /// copying over the tree's structure and node ids untouched.
+    pub fn map_ref<F, U>(&self, mut transform: F) -> Tree<U>
+    where
+        F: FnMut(&T) -> U,
+    {
+        Tree {
+            vec: self
+                .vec
+                .iter()
+                .map(|node| node.map_ref(&mut transform))
+                .collect(),
+        }
+    }
+}
+
+impl<'a, T: 'a> NodeRef<'a, T> {
+    /// Returns the ID of this node.
+    pub fn id(&self) -> NodeId {
+        self.id
+    }
+
+    /// Returns the tree owning this node.
+    pub fn tree(&self) -> &'a Tree<T> {
+        self.tree
+    }
+
+    /// Returns the value of this node.
+    pub fn value(&self) -> &'a T {
+        &self.node.value
+    }
+
+    fn axis<F>(&self, f: F) -> Option<Self>
+    where
+        F: FnOnce(&Node<T>) -> Option<NodeId>,
+    {
+        f(self.node).map(|id| unsafe { self.tree.get_unchecked(id) })
+    }
+
+    /// Returns the parent of this node.
+    pub fn parent(&self) -> Option<Self> {
+        self.axis(|node| node.parent)
+    }
+
+    /// Returns the previous sibling of this node.
+    pub fn prev_sibling(&self) -> Option<Self> {
+        self.axis(|node| node.prev_sibling)
+    }
+
+    /// Returns the next sibling of this node.
+    pub fn next_sibling(&self) -> Option<Self> {
+        self.axis(|node| node.next_sibling)
+    }
+
+    /// Returns the first child of this node.
+    pub fn first_child(&self) -> Option<Self> {
+        self.axis(|node| node.children.map(|(id, _)| id))
+    }
+
+    /// Returns the last child of this node.
+    pub fn last_child(&self) -> Option<Self> {
+        self.axis(|node| node.children.map(|(_, id)| id))
+    }
+
+    /// Returns true if this node has siblings.
+    pub fn has_siblings(&self) -> bool {
+        self.node.prev_sibling.is_some() || self.node.next_sibling.is_some()
+    }
+
+    /// Returns true if this node has children.
+    pub fn has_children(&self) -> bool {
+        self.node.children.is_some()
+    }
+}
+
+impl<'a, T: 'a> NodeMut<'a, T> {
+    /// Returns the ID of this node.
+    pub fn id(&self) -> NodeId {
+        self.id
+    }
+
+    /// Returns the tree owning this node.
+    pub fn tree(&mut self) -> &mut Tree<T> {
+        self.tree
+    }
+
+    fn node(&mut self) -> &mut Node<T> {
+        unsafe { self.tree.node_mut(self.id) }
+    }
+
+    /// Returns the value of this node.
+    pub fn value(&mut self) -> &mut T {
+        &mut self.node().value
+    }
+
+    fn axis<F>(&mut self, f: F) -> Option<NodeMut<T>>
+    where
+        F: FnOnce(&mut Node<T>) -> Option<NodeId>,
+    {
+        let id = f(self.node());
+        id.map(move |id| unsafe { self.tree.get_unchecked_mut(id) })
+    }
+
+    fn into_axis<F>(mut self, f: F) -> Result<Self, Self>
+    where
+        F: FnOnce(&mut Node<T>) -> Option<NodeId>,
+    {
+        let id = f(self.node());
+        match id {
+            Some(id) => Ok(unsafe { self.tree.get_unchecked_mut(id) }),
+            None => Err(self),
+        }
+    }
+
+    /// Returns the parent of this node.
+    pub fn parent(&mut self) -> Option<NodeMut<T>> {
+        self.axis(|node| node.parent)
+    }
+
+    /// Returns the parent of this node.
+    ///
+    /// Returns `Ok(parent)` if possible and `Err(self)` otherwise
+    /// so the caller can recover the current position.
+    pub fn into_parent(self) -> Result<Self, Self> {
+        self.into_axis(|node| node.parent)
+    }
+
+    /// Returns the previous sibling of this node.
+    pub fn prev_sibling(&mut self) -> Option<NodeMut<T>> {
+        self.axis(|node| node.prev_sibling)
+    }
+
+    /// Returns the previous sibling of this node.
+    ///
+    /// Returns `Ok(prev_sibling)` if possible and `Err(self)` otherwise
+    /// so the caller can recover the current position.
+    pub fn into_prev_sibling(self) -> Result<Self, Self> {
+        self.into_axis(|node| node.prev_sibling)
+    }
+
+    /// Returns the next sibling of this node.
+    pub fn next_sibling(&mut self) -> Option<NodeMut<T>> {
+        self.axis(|node| node.next_sibling)
+    }
+
+    /// Returns the next sibling of this node.
+    ///
+    /// Returns `Ok(next_sibling)` if possible and `Err(self)` otherwise
+    /// so the caller can recover the current position.
+    pub fn into_next_sibling(self) -> Result<Self, Self> {
+        self.into_axis(|node| node.next_sibling)
+    }
+
+    /// Returns the first child of this node.
+    pub fn first_child(&mut self) -> Option<NodeMut<T>> {
+        self.axis(|node| node.children.map(|(id, _)| id))
+    }
+
+    /// Returns the first child of this node.
+    ///
+    /// Returns `Ok(first_child)` if possible and `Err(self)` otherwise
+    /// so the caller can recover the current position.
+    pub fn into_first_child(self) -> Result<Self, Self> {
+        self.into_axis(|node| node.children.map(|(id, _)| id))
+    }
+
+    /// Returns the last child of this node.
+    pub fn last_child(&mut self) -> Option<NodeMut<T>> {
+        self.axis(|node| node.children.map(|(_, id)| id))
+    }
+
+    /// Returns the last child of this node.
+    ///
+    /// Returns `Ok(last_child)` if possible and `Err(self)` otherwise
+    /// so the caller can recover the current position.
+    pub fn into_last_child(self) -> Result<Self, Self> {
+        self.into_axis(|node| node.children.map(|(_, id)| id))
+    }
+
+    /// Returns true if this node has siblings.
+    pub fn has_siblings(&self) -> bool {
+        unsafe { self.tree.get_unchecked(self.id).has_siblings() }
+    }
+
+    /// Returns true if this node has children.
+    pub fn has_children(&self) -> bool {
+        unsafe { self.tree.get_unchecked(self.id).has_children() }
+    }
+
+    /// Appends a new child to this node.
+    pub fn append(&mut self, value: T) -> NodeMut<T> {
+        let id = self.tree.orphan(value).id;
+        self.append_id(id)
+    }
+
+    /// Prepends a new child to this node.
+    pub fn prepend(&mut self, value: T) -> NodeMut<T> {
+        let id = self.tree.orphan(value).id;
+        self.prepend_id(id)
+    }
+
+    /// Appends a subtree, return the root of the merged subtree.
+    pub fn append_subtree(&mut self, subtree: Tree<T>) -> NodeMut<T> {
+        let root_id = self.tree.extend_tree(subtree).id;
+        self.append_id(root_id)
+    }
+
+    /// Prepends a subtree, return the root of the merged subtree.
+    pub fn prepend_subtree(&mut self, subtree: Tree<T>) -> NodeMut<T> {
+        let root_id = self.tree.extend_tree(subtree).id;
+        self.prepend_id(root_id)
+    }
+
+    /// Inserts a new sibling before this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if this node is an orphan.
+    pub fn insert_before(&mut self, value: T) -> NodeMut<T> {
+        let id = self.tree.orphan(value).id;
+        self.insert_id_before(id)
+    }
+
+    /// Inserts a new sibling after this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if this node is an orphan.
+    pub fn insert_after(&mut self, value: T) -> NodeMut<T> {
+        let id = self.tree.orphan(value).id;
+        self.insert_id_after(id)
+    }
+
+    /// Detaches this node from its parent.
+    pub fn detach(&mut self) {
+        let parent_id = match self.node().parent {
+            Some(id) => id,
+            None => return,
+        };
+        let prev_sibling_id = self.node().prev_sibling;
+        let next_sibling_id = self.node().next_sibling;
+
+        {
+            self.node().parent = None;
+            self.node().prev_sibling = None;
+            self.node().next_sibling = None;
+        }
+
+        if let Some(id) = prev_sibling_id {
+            unsafe {
+                self.tree.node_mut(id).next_sibling = next_sibling_id;
+            }
+        }
+        if let Some(id) = next_sibling_id {
+            unsafe {
+                self.tree.node_mut(id).prev_sibling = prev_sibling_id;
+            }
+        }
+
+        let parent = unsafe { self.tree.node_mut(parent_id) };
+        let (first_child_id, last_child_id) = parent.children.unwrap();
+        if first_child_id == last_child_id {
+            parent.children = None;
+        } else if first_child_id == self.id {
+            parent.children = Some((next_sibling_id.unwrap(), last_child_id));
+        } else if last_child_id == self.id {
+            parent.children = Some((first_child_id, prev_sibling_id.unwrap()));
+        }
+    }
+
+    /// Appends a child to this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `new_child_id` is not valid.
+    pub fn append_id(&mut self, new_child_id: NodeId) -> NodeMut<T> {
+        assert_ne!(
+            self.id(),
+            new_child_id,
+            "Cannot append node as a child to itself"
+        );
+
+        let last_child_id = self.node().children.map(|(_, id)| id);
+
+        if last_child_id != Some(new_child_id) {
+            {
+                let mut new_child = self.tree.get_mut(new_child_id).unwrap();
+                new_child.detach();
+                new_child.node().parent = Some(self.id);
+                new_child.node().prev_sibling = last_child_id;
+            }
+
+            if let Some(id) = last_child_id {
+                unsafe {
+                    self.tree.node_mut(id).next_sibling = Some(new_child_id);
+                }
+            }
+
+            {
+                self.node().children = match self.node().children {
+                    Some((first_child_id, _)) => Some((first_child_id, new_child_id)),
+                    None => Some((new_child_id, new_child_id)),
+                };
+            }
+        }
+
+        unsafe { self.tree.get_unchecked_mut(new_child_id) }
+    }
+
+    /// Prepends a child to this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `new_child_id` is not valid.
+    pub fn prepend_id(&mut self, new_child_id: NodeId) -> NodeMut<T> {
+        assert_ne!(
+            self.id(),
+            new_child_id,
+            "Cannot prepend node as a child to itself"
+        );
+
+        let first_child_id = self.node().children.map(|(id, _)| id);
+
+        if first_child_id != Some(new_child_id) {
+            {
+                let mut new_child = self.tree.get_mut(new_child_id).unwrap();
+                new_child.detach();
+                new_child.node().parent = Some(self.id);
+                new_child.node().next_sibling = first_child_id;
+            }
+
+            if let Some(id) = first_child_id {
+                unsafe {
+                    self.tree.node_mut(id).prev_sibling = Some(new_child_id);
+                }
+            }
+
+            {
+                self.node().children = match self.node().children {
+                    Some((_, last_child_id)) => Some((new_child_id, last_child_id)),
+                    None => Some((new_child_id, new_child_id)),
+                };
+            }
+        }
+
+        unsafe { self.tree.get_unchecked_mut(new_child_id) }
+    }
+
+    /// Inserts a sibling before this node.
+    ///
+    /// # Panics
+    ///
+    /// - Panics if `new_sibling_id` is not valid.
+    /// - Panics if this node is an orphan.
+    pub fn insert_id_before(&mut self, new_sibling_id: NodeId) -> NodeMut<T> {
+        assert_ne!(
+            self.id(),
+            new_sibling_id,
+            "Cannot insert node as a sibling of itself"
+        );
+
+        let parent_id = self.node().parent.unwrap();
+        let prev_sibling_id = self.node().prev_sibling;
+
+        {
+            let mut new_sibling = self.tree.get_mut(new_sibling_id).unwrap();
+            new_sibling.detach();
+            new_sibling.node().parent = Some(parent_id);
+            new_sibling.node().prev_sibling = prev_sibling_id;
+            new_sibling.node().next_sibling = Some(self.id);
+        }
+
+        if let Some(id) = prev_sibling_id {
+            unsafe {
+                self.tree.node_mut(id).next_sibling = Some(new_sibling_id);
+            }
+        }
+
+        self.node().prev_sibling = Some(new_sibling_id);
+
+        {
+            let parent = unsafe { self.tree.node_mut(parent_id) };
+            let (first_child_id, last_child_id) = parent.children.unwrap();
+            if first_child_id == self.id {
+                parent.children = Some((new_sibling_id, last_child_id));
+            }
+        }
+
+        unsafe { self.tree.get_unchecked_mut(new_sibling_id) }
+    }
+
+    /// Inserts a sibling after this node.
+    ///
+    /// # Panics
+    ///
+    /// - Panics if `new_sibling_id` is not valid.
+    /// - Panics if this node is an orphan.
+    pub fn insert_id_after(&mut self, new_sibling_id: NodeId) -> NodeMut<T> {
+        assert_ne!(
+            self.id(),
+            new_sibling_id,
+            "Cannot insert node as a sibling of itself"
+        );
+
+        let parent_id = self.node().parent.unwrap();
+        let next_sibling_id = self.node().next_sibling;
+
+        {
+            let mut new_sibling = self.tree.get_mut(new_sibling_id).unwrap();
+            new_sibling.detach();
+            new_sibling.node().parent = Some(parent_id);
+            new_sibling.node().prev_sibling = Some(self.id);
+            new_sibling.node().next_sibling = next_sibling_id;
+        }
+
+        if let Some(id) = next_sibling_id {
+            unsafe {
+                self.tree.node_mut(id).prev_sibling = Some(new_sibling_id);
+            }
+        }
+
+        self.node().next_sibling = Some(new_sibling_id);
+
+        {
+            let parent = unsafe { self.tree.node_mut(parent_id) };
+            let (first_child_id, last_child_id) = parent.children.unwrap();
+            if last_child_id == self.id {
+                parent.children = Some((first_child_id, new_sibling_id));
+            }
+        }
+
+        unsafe { self.tree.get_unchecked_mut(new_sibling_id) }
+    }
+
+    /// Reparents the children of a node, appending them to this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `from_id` is not valid.
+    pub fn reparent_from_id_append(&mut self, from_id: NodeId) {
+        assert_ne!(
+            self.id(),
+            from_id,
+            "Cannot reparent node's children to itself"
+        );
+
+        let new_child_ids = {
+            let mut from = self.tree.get_mut(from_id).unwrap();
+            match from.node().children.take() {
+                Some(ids) => ids,
+                None => return,
+            }
+        };
+
+        unsafe {
+            self.tree.node_mut(new_child_ids.0).parent = Some(self.id);
+            self.tree.node_mut(new_child_ids.1).parent = Some(self.id);
+        }
+
+        if self.node().children.is_none() {
+            self.node().children = Some(new_child_ids);
+            return;
+        }
+
+        let old_child_ids = self.node().children.unwrap();
+        unsafe {
+            self.tree.node_mut(old_child_ids.1).next_sibling = Some(new_child_ids.0);
+            self.tree.node_mut(new_child_ids.0).prev_sibling = Some(old_child_ids.1);
+        }
+
+        self.node().children = Some((old_child_ids.0, new_child_ids.1));
+    }
+
+    /// Reparents the children of a node, prepending them to this node.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `from_id` is not valid.
+    pub fn reparent_from_id_prepend(&mut self, from_id: NodeId) {
+        assert_ne!(
+            self.id(),
+            from_id,
+            "Cannot reparent node's children to itself"
+        );
+
+        let new_child_ids = {
+            let mut from = self.tree.get_mut(from_id).unwrap();
+            match from.node().children.take() {
+                Some(ids) => ids,
+                None => return,
+            }
+        };
+
+        unsafe {
+            self.tree.node_mut(new_child_ids.0).parent = Some(self.id);
+            self.tree.node_mut(new_child_ids.1).parent = Some(self.id);
+        }
+
+        if self.node().children.is_none() {
+            self.node().children = Some(new_child_ids);
+            return;
+        }
+
+        let old_child_ids = self.node().children.unwrap();
+        unsafe {
+            self.tree.node_mut(old_child_ids.0).prev_sibling = Some(new_child_ids.1);
+            self.tree.node_mut(new_child_ids.1).next_sibling = Some(old_child_ids.0);
+        }
+
+        self.node().children = Some((new_child_ids.0, old_child_ids.1));
+    }
+}
+
+impl<'a, T: 'a> From<NodeMut<'a, T>> for NodeRef<'a, T> {
+    fn from(node: NodeMut<'a, T>) -> Self {
+        unsafe { node.tree.get_unchecked(node.id) }
+    }
+}
+
+/// Iterators.
+pub mod iter;
+
+/// Creates a tree from expressions.
+///
+/// # Examples
+///
+/// ```
+/// #[macro_use] extern crate ego_tree;
+/// # fn main() {
+/// let tree = tree!("root");
+/// # }
+/// ```
+///
+/// ```
+/// #[macro_use] extern crate ego_tree;
+/// # fn main() {
+/// let tree = tree! {
+///     "root" => {
+///         "child a",
+///         "child b" => {
+///             "grandchild a",
+///             "grandchild b",
+///         },
+///         "child c",
+///     }
+/// };
+/// # }
+/// ```
+#[macro_export]
+macro_rules! tree {
+    (@ $n:ident { }) => { };
+
+    // Last leaf.
+    (@ $n:ident { $value:expr }) => {
+        { $n.append($value); }
+    };
+
+    // Leaf.
+    (@ $n:ident { $value:expr, $($tail:tt)* }) => {
+        {
+            $n.append($value);
+            tree!(@ $n { $($tail)* });
+        }
+    };
+
+    // Last node with children.
+    (@ $n:ident { $value:expr => $children:tt }) => {
+        {
+            let mut node = $n.append($value);
+            tree!(@ node $children);
+        }
+    };
+
+    // Node with children.
+    (@ $n:ident { $value:expr => $children:tt, $($tail:tt)* }) => {
+        {
+            {
+                let mut node = $n.append($value);
+                tree!(@ node $children);
+            }
+            tree!(@ $n { $($tail)* });
+        }
+    };
+
+    ($root:expr) => { $crate::Tree::new($root) };
+
+    ($root:expr => $children:tt) => {
+        {
+            let mut tree = $crate::Tree::new($root);
+            {
+                let mut node = tree.root_mut();
+                tree!(@ node $children);
+            }
+            tree
+        }
+    };
+}
+
+impl<T: Debug> Debug for Tree<T> {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+        use crate::iter::Edge;
+        if f.alternate() {
+            write!(f, "Tree {{")?;
+            for edge in self.root().traverse() {
+                match edge {
+                    Edge::Open(node) if node.has_children() => {
+                        write!(f, " {:?} => {{", node.value())?;
+                    }
+                    Edge::Open(node) if node.next_sibling().is_some() => {
+                        write!(f, " {:?},", node.value())?;
+                    }
+                    Edge::Open(node) => {
+                        write!(f, " {:?}", node.value())?;
+                    }
+                    Edge::Close(node) if node.has_children() => {
+                        if node.next_sibling().is_some() {
+                            write!(f, " }},")?;
+                        } else {
+                            write!(f, " }}")?;
+                        }
+                    }
+                    _ => {}
+                }
+            }
+            write!(f, " }}")
+        } else {
+            f.debug_struct("Tree").field("vec", &self.vec).finish()
+        }
+    }
+}
+
+// Handles display
+mod display;
+
+impl<T: Display> Display for Tree<T> {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+        use crate::display::Indentation;
+        use crate::iter::Edge;
+
+        let mut indent: Indentation = Indentation::new(true);
+
+        for edge in self.root().traverse() {
+            match edge {
+                Edge::Open(node) if node.has_children() => {
+                    indent.indent(node.next_sibling().is_some());
+                    writeln!(f, "{indent}{}", node.value())?;
+                }
+                Edge::Open(node) => {
+                    indent.indent(node.next_sibling().is_some());
+                    writeln!(f, "{indent}{}", node.value())?;
+                    indent.deindent();
+                }
+                Edge::Close(node) if node.has_children() => {
+                    indent.deindent();
+                }
+                _ => {}
+            }
+        }
+        Ok(())
+    }
+}
+
+mod sort;
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/serde.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/serde.rs
new file mode 100644
index 000000000000..4fed0b36ad32
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/serde.rs
@@ -0,0 +1,157 @@
+//! Implement `serde::Serialize` and `serde::Deserialize` traits for Tree
+//!
+//! # Warning
+//! Serialize and Deserialize implementations are recursive. They require an amount of stack memory
+//! proportional to the depth of the tree.
+
+use std::{fmt, marker::PhantomData};
+
+use serde::{
+    de::{self, MapAccess, Visitor},
+    ser::{Serialize, SerializeStruct},
+    Deserialize, Deserializer,
+};
+
+use crate::{NodeMut, NodeRef, Tree};
+
+#[derive(Debug)]
+struct SerNode<'a, T> {
+    value: &'a T,
+    children: Vec<SerNode<'a, T>>,
+}
+
+impl<'a, T> From<NodeRef<'a, T>> for SerNode<'a, T> {
+    fn from(node: NodeRef<'a, T>) -> Self {
+        let value = node.value();
+        let children = node.children().map(SerNode::from).collect();
+        Self { value, children }
+    }
+}
+
+impl<T: Serialize> Serialize for SerNode<'_, T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        let mut state = serializer.serialize_struct("Node", 2)?;
+        state.serialize_field("value", &self.value)?;
+        state.serialize_field("children", &self.children)?;
+        state.end()
+    }
+}
+
+impl<T: Serialize> Serialize for Tree<T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        SerNode::from(self.root()).serialize(serializer)
+    }
+}
+
+#[derive(Debug)]
+struct DeserNode<T> {
+    value: T,
+    children: Vec<DeserNode<T>>,
+}
+
+impl<T> DeserNode<T> {
+    fn into_tree_node(self, parent: &mut NodeMut<T>) {
+        let mut node = parent.append(self.value);
+
+        for child in self.children {
+            child.into_tree_node(&mut node);
+        }
+    }
+}
+
+impl<T> From<DeserNode<T>> for Tree<T> {
+    fn from(root: DeserNode<T>) -> Self {
+        let mut tree: Tree<T> = Tree::new(root.value);
+        let mut tree_root = tree.root_mut();
+
+        for child in root.children {
+            child.into_tree_node(&mut tree_root);
+        }
+
+        tree
+    }
+}
+
+struct DeserNodeVisitor<T> {
+    marker: PhantomData<fn() -> DeserNode<T>>,
+}
+
+impl<T> DeserNodeVisitor<T> {
+    fn new() -> Self {
+        DeserNodeVisitor {
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<'de, T> Visitor<'de> for DeserNodeVisitor<T>
+where
+    T: Deserialize<'de>,
+{
+    type Value = DeserNode<T>;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("struct Node")
+    }
+
+    fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
+    where
+        M: MapAccess<'de>,
+    {
+        let mut value = None;
+        let mut children = None;
+
+        while let Some(key) = map.next_key()? {
+            match key {
+                "value" => {
+                    if value.is_some() {
+                        return Err(de::Error::duplicate_field("value"));
+                    }
+                    value = Some(map.next_value()?);
+                }
+                "children" => {
+                    if children.is_some() {
+                        return Err(de::Error::duplicate_field("children"));
+                    }
+                    children = Some(map.next_value()?);
+                }
+                _ => {
+                    return Err(de::Error::unknown_field(key, &["value", "children"]));
+                }
+            }
+        }
+
+        let value = value.ok_or_else(|| de::Error::missing_field("value"))?;
+        let children = children.ok_or_else(|| de::Error::missing_field("children"))?;
+
+        Ok(DeserNode { value, children })
+    }
+}
+
+impl<'de, T> Deserialize<'de> for DeserNode<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_struct("Node", &["value", "children"], DeserNodeVisitor::new())
+    }
+}
+
+impl<'de, T: Deserialize<'de>> Deserialize<'de> for Tree<T> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let deser = DeserNode::<T>::deserialize(deserializer)?;
+        Ok(deser.into())
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/sort.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/sort.rs
new file mode 100644
index 000000000000..1fff86e0d421
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/sort.rs
@@ -0,0 +1,120 @@
+//! Sorting functionality for tree nodes.
+//!
+//! This module provides methods for sorting children of a node in a tree.
+//! The sorting can be done based on the node values or their indices.
+
+use std::cmp::Ordering;
+
+use crate::{NodeMut, NodeRef};
+
+impl<'a, T: 'a> NodeMut<'a, T> {
+    /// Sort children by value in ascending order.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use ego_tree::tree;
+    ///
+    /// let mut tree = tree!('a' => { 'd', 'c', 'b' });
+    /// tree.root_mut().sort();
+    /// assert_eq!(
+    ///     vec![&'b', &'c', &'d'],
+    ///     tree.root()
+    ///         .children()
+    ///         .map(|n| n.value())
+    ///         .collect::<Vec<_>>(),
+    /// );
+    /// ```
+    pub fn sort(&mut self)
+    where
+        T: Ord,
+    {
+        self.sort_by(|a, b| a.value().cmp(b.value()));
+    }
+
+    /// Sort children by `NodeRef` in ascending order using a comparison function.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use ego_tree::tree;
+    ///
+    /// let mut tree = tree!('a' => { 'c', 'd', 'b' });
+    /// tree.root_mut().sort_by(|a, b| b.value().cmp(a.value()));
+    /// assert_eq!(
+    ///     vec![&'d', &'c', &'b'],
+    ///     tree.root()
+    ///         .children()
+    ///         .map(|n| n.value())
+    ///         .collect::<Vec<_>>(),
+    /// );
+    ///
+    /// // Example for sort_by_id.
+    /// tree.root_mut().sort_by(|a, b| a.id().cmp(&b.id()));
+    /// assert_eq!(
+    ///     vec![&'c', &'d', &'b'],
+    ///     tree.root()
+    ///         .children()
+    ///         .map(|n| n.value())
+    ///         .collect::<Vec<_>>(),
+    /// );
+    /// ```
+    pub fn sort_by<F>(&mut self, mut compare: F)
+    where
+        F: FnMut(NodeRef<T>, NodeRef<T>) -> Ordering,
+    {
+        if !self.has_children() {
+            return;
+        }
+
+        let mut children = {
+            let this = unsafe { self.tree.get_unchecked(self.id) };
+            this.children().map(|child| child.id).collect::<Vec<_>>()
+        };
+
+        children.sort_by(|a, b| {
+            let a = unsafe { self.tree.get_unchecked(*a) };
+            let b = unsafe { self.tree.get_unchecked(*b) };
+            compare(a, b)
+        });
+
+        for id in children {
+            self.append_id(id);
+        }
+    }
+
+    /// Sort children by `NodeRef`'s key in ascending order using a key extraction function.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use ego_tree::tree;
+    ///
+    /// let mut tree = tree!("1a" => { "2b", "4c", "3d" });
+    /// tree.root_mut().sort_by_key(|a| a.value().split_at(1).0.parse::<i32>().unwrap());
+    /// assert_eq!(
+    ///     vec!["2b", "3d", "4c"],
+    ///     tree.root()
+    ///         .children()
+    ///         .map(|n| *n.value())
+    ///         .collect::<Vec<_>>(),
+    /// );
+    ///
+    /// // Example for sort_by_id.
+    /// tree.root_mut().sort_by_key(|n| n.id());
+    /// assert_eq!(
+    ///     vec![&"2b", &"4c", &"3d"],
+    ///     tree.root()
+    ///         .children()
+    ///         .map(|n| n.value())
+    ///         .collect::<Vec<_>>(),
+    /// );
+    /// ```
+    pub fn sort_by_key<K, F>(&mut self, mut f: F)
+    where
+        F: FnMut(NodeRef<T>) -> K,
+        K: Ord,
+    {
+        self.sort_by(|a, b| f(a).cmp(&f(b)));
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/iter.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/iter.rs
new file mode 100644
index 000000000000..5ce441a2cca9
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/iter.rs
@@ -0,0 +1,236 @@
+use ego_tree::tree;
+
+#[test]
+fn into_iter() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec!['a', 'b', 'c', 'd'],
+        tree.into_iter().collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn values() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec![&'a', &'b', &'c', &'d'],
+        tree.values().collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn values_mut() {
+    let mut tree = tree!('a' => { 'b', 'c', 'd' });
+
+    for c in tree.values_mut() {
+        *c = c.to_ascii_uppercase();
+    }
+
+    assert_eq!(
+        vec![&'A', &'B', &'C', &'D'],
+        tree.values().collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn nodes() {
+    let mut tree = tree!('a' => { 'b' => { 'c' }, 'd' });
+    tree.orphan('e').append('f');
+    tree.root_mut().append('g');
+    assert_eq!(
+        vec![&'a', &'b', &'c', &'d', &'e', &'f', &'g'],
+        tree.nodes().map(|n| n.value()).collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn ancestors() {
+    let tree = tree!('a' => { 'b' => { 'c' => { 'd' } } });
+    let d = tree
+        .root()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap();
+    assert_eq!(
+        vec![&'c', &'b', &'a'],
+        d.ancestors().map(|n| n.value()).collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn ancestors_fused() {
+    let tree = tree!('a' => { 'b' => { 'c' => { 'd' } } });
+    let d = tree
+        .root()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap()
+        .last_child()
+        .unwrap();
+
+    let mut ancestors = d.ancestors();
+    assert_eq!(ancestors.by_ref().count(), 3);
+    assert_eq!(ancestors.next(), None);
+}
+
+#[test]
+fn prev_siblings() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec![&'c', &'b'],
+        tree.root()
+            .last_child()
+            .unwrap()
+            .prev_siblings()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn next_siblings() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec![&'c', &'d'],
+        tree.root()
+            .first_child()
+            .unwrap()
+            .next_siblings()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn children() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec![&'b', &'c', &'d'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn children_fused() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+
+    let mut children = tree.root().children();
+
+    assert_eq!(children.by_ref().count(), 3);
+    assert_eq!(children.next(), None);
+}
+
+#[test]
+fn children_rev() {
+    let tree = tree!('a' => { 'b', 'c', 'd' });
+    assert_eq!(
+        vec![&'d', &'c', &'b'],
+        tree.root()
+            .children()
+            .rev()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn first_children() {
+    let tree = tree!('a' => { 'b' => { 'd', 'e' }, 'c' });
+    assert_eq!(
+        vec![&'b', &'d'],
+        tree.root()
+            .first_children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn last_children() {
+    let tree = tree!('a' => { 'b', 'c' => { 'd', 'e' } });
+    assert_eq!(
+        vec![&'c', &'e'],
+        tree.root()
+            .last_children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>()
+    );
+}
+
+#[test]
+fn traverse() {
+    use ego_tree::iter::Edge;
+
+    #[derive(Debug, PartialEq, Eq)]
+    enum Value<'a> {
+        Open(&'a char),
+        Close(&'a char),
+    }
+
+    let tree = tree!('a' => { 'b' => { 'd', 'e' }, 'c' });
+
+    let traversal = tree
+        .root()
+        .traverse()
+        .map(|edge| match edge {
+            Edge::Open(node) => Value::Open(node.value()),
+            Edge::Close(node) => Value::Close(node.value()),
+        })
+        .collect::<Vec<_>>();
+
+    assert_eq!(
+        &[
+            Value::Open(&'a'),
+            Value::Open(&'b'),
+            Value::Open(&'d'),
+            Value::Close(&'d'),
+            Value::Open(&'e'),
+            Value::Close(&'e'),
+            Value::Close(&'b'),
+            Value::Open(&'c'),
+            Value::Close(&'c'),
+            Value::Close(&'a'),
+        ],
+        &traversal[..]
+    );
+}
+
+#[test]
+fn traverse_fused() {
+    let tree = tree!('a' => { 'b' => { 'd', 'e' }, 'c' });
+
+    let mut traversal = tree.root().traverse();
+
+    assert_eq!(traversal.by_ref().count(), 2 * 5);
+    assert_eq!(traversal.next(), None);
+}
+
+#[test]
+fn descendants() {
+    let tree = tree!('a' => { 'b' => { 'd', 'e' }, 'c' });
+
+    let descendants = tree
+        .root()
+        .descendants()
+        .map(|n| n.value())
+        .collect::<Vec<_>>();
+
+    assert_eq!(&[&'a', &'b', &'d', &'e', &'c',], &descendants[..]);
+}
+
+#[test]
+fn descendants_fused() {
+    let tree = tree!('a' => { 'b' => { 'd', 'e' }, 'c' });
+
+    let mut descendants = tree.root().descendants();
+
+    assert_eq!(descendants.by_ref().count(), 5);
+    assert_eq!(descendants.next(), None);
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/macro.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/macro.rs
new file mode 100644
index 000000000000..377fb8f366e1
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/macro.rs
@@ -0,0 +1,165 @@
+use ego_tree::{tree, Tree};
+
+#[test]
+fn root() {
+    let macro_tree = tree!('a');
+    let manual_tree = Tree::new('a');
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn single_child() {
+    let macro_tree = tree!('a' => { 'b' });
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn single_child_comma() {
+    let macro_tree = tree! {
+        'a' => {
+            'b',
+        }
+    };
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn leaves() {
+    let macro_tree = tree!('a' => { 'b', 'c', 'd' });
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b');
+    manual_tree.root_mut().append('c');
+    manual_tree.root_mut().append('d');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn leaves_comma() {
+    let macro_tree = tree! {
+        'a' => {
+            'b',
+            'c',
+            'd',
+        }
+    };
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b');
+    manual_tree.root_mut().append('c');
+    manual_tree.root_mut().append('d');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn nested_single_child() {
+    let macro_tree = tree!('a' => { 'b' => { 'c' } });
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b').append('c');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn nested_single_child_comma() {
+    let macro_tree = tree! {
+        'a' => {
+            'b' => {
+                'c',
+            },
+        }
+    };
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b').append('c');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn nested_leaves() {
+    let macro_tree = tree!('a' => { 'b' => { 'c', 'd', 'e' } });
+
+    let mut manual_tree = Tree::new('a');
+    {
+        let mut root = manual_tree.root_mut();
+        let mut node = root.append('b');
+        node.append('c');
+        node.append('d');
+        node.append('e');
+    }
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn nested_leaves_comma() {
+    let macro_tree = tree! {
+        'a' => {
+            'b' => {
+                'c',
+                'd',
+                'e',
+            },
+        }
+    };
+
+    let mut manual_tree = Tree::new('a');
+    {
+        let mut root = manual_tree.root_mut();
+        let mut node = root.append('b');
+        node.append('c');
+        node.append('d');
+        node.append('e');
+    }
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn nested_nested() {
+    let macro_tree = tree!('a' => { 'b' => { 'c' => { 'd' } } });
+
+    let mut manual_tree = Tree::new('a');
+    manual_tree.root_mut().append('b').append('c').append('d');
+
+    assert_eq!(manual_tree, macro_tree);
+}
+
+#[test]
+fn mixed() {
+    let macro_tree = tree! {
+        'a' => {
+            'b',
+            'd' => { 'e', 'f' },
+            'g' => { 'h' => { 'i' } },
+            'j',
+        }
+    };
+
+    let mut manual_tree = Tree::new('a');
+    {
+        let mut node = manual_tree.root_mut();
+        node.append('b');
+        {
+            let mut d = node.append('d');
+            d.append('e');
+            d.append('f');
+        }
+        node.append('g').append('h').append('i');
+        node.append('j');
+    }
+
+    assert_eq!(manual_tree, macro_tree);
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_mut.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_mut.rs
new file mode 100644
index 000000000000..8208bf8cf0ce
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_mut.rs
@@ -0,0 +1,429 @@
+use ego_tree::{tree, NodeRef};
+
+#[test]
+fn value() {
+    let mut tree = tree!('a');
+    assert_eq!(&'a', tree.root_mut().value());
+}
+
+#[test]
+fn parent() {
+    let mut tree = tree!('a' => { 'b' });
+    assert_eq!(
+        &'a',
+        tree.root_mut()
+            .first_child()
+            .unwrap()
+            .parent()
+            .unwrap()
+            .value()
+    );
+}
+
+#[test]
+fn prev_sibling() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(
+        &'b',
+        tree.root_mut()
+            .last_child()
+            .unwrap()
+            .prev_sibling()
+            .unwrap()
+            .value()
+    );
+}
+
+#[test]
+fn next_sibling() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(
+        &'c',
+        tree.root_mut()
+            .first_child()
+            .unwrap()
+            .next_sibling()
+            .unwrap()
+            .value()
+    );
+}
+
+#[test]
+fn first_child() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(&'b', tree.root_mut().first_child().unwrap().value());
+}
+
+#[test]
+fn last_child() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(&'c', tree.root_mut().last_child().unwrap().value());
+}
+
+#[test]
+fn has_siblings() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert!(tree.root_mut().first_child().unwrap().has_siblings());
+    assert!(!tree.root_mut().has_siblings());
+}
+
+#[test]
+fn has_children() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    assert!(tree.root_mut().has_children());
+    assert!(!tree.root_mut().first_child().unwrap().has_children());
+}
+
+#[test]
+fn append_1() {
+    let mut tree = tree!('a');
+    tree.root_mut().append('b');
+
+    let root = tree.root();
+    let child = root.first_child().unwrap();
+
+    assert_eq!(&'b', child.value());
+    assert_eq!(Some(child), root.last_child());
+    assert_eq!(Some(root), child.parent());
+    assert_eq!(None, child.next_sibling());
+    assert_eq!(None, child.next_sibling());
+}
+
+#[test]
+fn append_2() {
+    let mut tree = tree!('a');
+    tree.root_mut().append('b');
+    tree.root_mut().append('c');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = root.last_child().unwrap();
+
+    assert_eq!(&'b', b.value());
+    assert_eq!(&'c', c.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(None, c.next_sibling());
+}
+
+#[test]
+fn append_3() {
+    let mut tree = tree!('a');
+    tree.root_mut().append('b');
+    tree.root_mut().append('c');
+    tree.root_mut().append('d');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = b.next_sibling().unwrap();
+    let d = root.last_child().unwrap();
+
+    assert_eq!(&'b', b.value());
+    assert_eq!(&'c', c.value());
+    assert_eq!(&'d', d.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(Some(root), d.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(Some(d), c.next_sibling());
+    assert_eq!(Some(c), d.prev_sibling());
+    assert_eq!(None, d.next_sibling());
+}
+
+#[test]
+fn prepend_1() {
+    let mut tree = tree!('a');
+    tree.root_mut().prepend('b');
+
+    let root = tree.root();
+    let child = root.first_child().unwrap();
+
+    assert_eq!(&'b', child.value());
+    assert_eq!(Some(child), root.last_child());
+    assert_eq!(Some(root), child.parent());
+    assert_eq!(None, child.next_sibling());
+    assert_eq!(None, child.next_sibling());
+}
+
+#[test]
+fn prepend_2() {
+    let mut tree = tree!('a');
+    tree.root_mut().prepend('c');
+    tree.root_mut().prepend('b');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = root.last_child().unwrap();
+
+    assert_eq!(&'b', b.value());
+    assert_eq!(&'c', c.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(None, c.next_sibling());
+}
+
+#[test]
+fn prepend_3() {
+    let mut tree = tree!('a');
+    tree.root_mut().prepend('d');
+    tree.root_mut().prepend('c');
+    tree.root_mut().prepend('b');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = b.next_sibling().unwrap();
+    let d = root.last_child().unwrap();
+
+    assert_eq!(&'b', b.value());
+    assert_eq!(&'c', c.value());
+    assert_eq!(&'d', d.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(Some(root), d.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(Some(d), c.next_sibling());
+    assert_eq!(Some(c), d.prev_sibling());
+    assert_eq!(None, d.next_sibling());
+}
+
+#[test]
+fn insert_before_first() {
+    let mut tree = tree!('a' => { 'c' });
+    tree.root_mut().first_child().unwrap().insert_before('b');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = root.last_child().unwrap();
+
+    assert_eq!(&'b', b.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(None, c.next_sibling());
+}
+
+#[test]
+fn insert_before() {
+    let mut tree = tree!('a' => { 'b', 'd' });
+    tree.root_mut().last_child().unwrap().insert_before('c');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = b.next_sibling().unwrap();
+    let d = root.last_child().unwrap();
+
+    assert_eq!(&'c', c.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(Some(root), d.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(Some(d), c.next_sibling());
+    assert_eq!(Some(c), d.prev_sibling());
+    assert_eq!(None, d.next_sibling());
+}
+
+#[test]
+fn insert_after_first() {
+    let mut tree = tree!('a' => { 'b' });
+    tree.root_mut().first_child().unwrap().insert_after('c');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = root.last_child().unwrap();
+
+    assert_eq!(&'c', c.value());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(None, c.next_sibling());
+}
+
+#[test]
+fn insert_after() {
+    let mut tree = tree!('a' => { 'b', 'd' });
+    tree.root_mut().first_child().unwrap().insert_after('c');
+
+    let root = tree.root();
+    let b = root.first_child().unwrap();
+    let c = b.next_sibling().unwrap();
+    let d = root.last_child().unwrap();
+
+    assert_eq!(&'c', c.value());
+    assert_eq!(Some(root), b.parent());
+    assert_eq!(Some(root), c.parent());
+    assert_eq!(Some(root), d.parent());
+    assert_eq!(None, b.prev_sibling());
+    assert_eq!(Some(c), b.next_sibling());
+    assert_eq!(Some(b), c.prev_sibling());
+    assert_eq!(Some(d), c.next_sibling());
+    assert_eq!(Some(c), d.prev_sibling());
+    assert_eq!(None, d.next_sibling());
+}
+
+#[test]
+fn insert_at_index() {
+    let mut tree = tree!('a' => { 'b', 'c', 'e' });
+
+    {
+        let mut root = tree.root_mut();
+        let mut child = root.first_child().unwrap();
+
+        for _ in 0..2 {
+            child = child.into_next_sibling().unwrap();
+        }
+
+        child.insert_before('d');
+    }
+
+    let descendants = tree
+        .root()
+        .descendants()
+        .map(|n| n.value())
+        .collect::<Vec<_>>();
+
+    assert_eq!(&[&'a', &'b', &'c', &'d', &'e',], &descendants[..]);
+}
+
+#[test]
+fn detach() {
+    let mut tree = tree!('a' => { 'b', 'd' });
+    let mut root = tree.root_mut();
+    let mut b = root.first_child().unwrap();
+    let mut c = b.insert_after('c');
+    c.detach();
+
+    assert!(c.parent().is_none());
+    assert!(c.prev_sibling().is_none());
+    assert!(c.next_sibling().is_none());
+}
+
+#[test]
+#[should_panic(expected = "Cannot append node as a child to itself")]
+fn append_id_itself() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'c', 'd' },
+            'e' => { 'f', 'g' },
+        }
+    };
+    let mut a = tree.root_mut();
+    let mut e = a.last_child().unwrap();
+    e.append_id(e.id());
+}
+
+#[test]
+fn append_id_noop() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'c', 'd' },
+            'e' => { 'f', 'g' },
+        }
+    };
+    let mut a = tree.root_mut();
+    let e_id = a.last_child().unwrap().id();
+    a.append_id(e_id);
+    assert_eq!(a.first_child().unwrap().next_sibling().unwrap().id(), e_id);
+}
+
+#[test]
+#[should_panic(expected = "Cannot prepend node as a child to itself")]
+fn prepend_id_itself() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'c', 'd' },
+            'e' => { 'f', 'g' },
+        }
+    };
+    let mut a = tree.root_mut();
+    let mut e = a.last_child().unwrap();
+    e.prepend_id(e.id());
+}
+
+#[test]
+fn prepend_id_noop() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'c', 'd' },
+            'e' => { 'f', 'g' },
+        }
+    };
+    let mut a = tree.root_mut();
+    let b_id = a.first_child().unwrap().id();
+    a.prepend_id(b_id);
+    assert_eq!(a.last_child().unwrap().prev_sibling().unwrap().id(), b_id);
+}
+
+#[test]
+fn reparent_from_id_append() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'c', 'd' },
+            'e' => { 'f', 'g' },
+        }
+    };
+    let e_id = tree.root().last_child().unwrap().id();
+    tree.root_mut()
+        .first_child()
+        .unwrap()
+        .reparent_from_id_append(e_id);
+
+    let b = tree.root().first_child().unwrap();
+    let e = tree.root().last_child().unwrap();
+    let d = b.first_child().unwrap().next_sibling().unwrap();
+    let g = b.last_child().unwrap();
+    let f = g.prev_sibling().unwrap();
+
+    assert!(!e.has_children());
+    assert_eq!(&'f', f.value());
+    assert_eq!(&'g', g.value());
+    assert_eq!(Some(f), d.next_sibling());
+    assert_eq!(Some(d), f.prev_sibling());
+}
+
+#[test]
+fn reparent_from_id_prepend() {
+    let mut tree = tree! {
+        'a' => {
+            'b' => { 'f', 'g' },
+            'e' => { 'c', 'd' },
+        }
+    };
+    let e_id = tree.root().last_child().unwrap().id();
+    tree.root_mut()
+        .first_child()
+        .unwrap()
+        .reparent_from_id_prepend(e_id);
+
+    let b = tree.root().first_child().unwrap();
+    let e = tree.root().last_child().unwrap();
+    let c = b.first_child().unwrap();
+    let d = c.next_sibling().unwrap();
+    let f = b.last_child().unwrap().prev_sibling().unwrap();
+
+    assert!(!e.has_children());
+    assert_eq!(&'c', c.value());
+    assert_eq!(&'d', d.value());
+    assert_eq!(Some(f), d.next_sibling());
+    assert_eq!(Some(d), f.prev_sibling());
+}
+
+#[test]
+fn into() {
+    let mut tree = tree!('a');
+    let node_ref: NodeRef<_> = tree.root_mut().into();
+    assert_eq!(&'a', node_ref.value());
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_ref.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_ref.rs
new file mode 100644
index 000000000000..af4dff850a8d
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/node_ref.rs
@@ -0,0 +1,83 @@
+use ego_tree::tree;
+
+#[test]
+fn value() {
+    let tree = tree!('a');
+    assert_eq!(&'a', tree.root().value());
+}
+
+#[test]
+fn parent() {
+    let tree = tree!('a' => { 'b' });
+    let b = tree.root().first_child().unwrap();
+    assert_eq!(tree.root(), b.parent().unwrap());
+}
+
+#[test]
+fn prev_sibling() {
+    let tree = tree!('a' => { 'b', 'c' });
+    let c = tree.root().last_child().unwrap();
+    assert_eq!(tree.root().first_child(), c.prev_sibling());
+}
+
+#[test]
+fn next_sibling() {
+    let tree = tree!('a' => { 'b', 'c' });
+    let b = tree.root().first_child().unwrap();
+    assert_eq!(tree.root().last_child(), b.next_sibling());
+}
+
+#[test]
+fn first_child() {
+    let tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(&'b', tree.root().first_child().unwrap().value());
+}
+
+#[test]
+fn last_child() {
+    let tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(&'c', tree.root().last_child().unwrap().value());
+}
+
+#[test]
+fn has_siblings() {
+    let tree = tree!('a' => { 'b', 'c' });
+    assert!(!tree.root().has_siblings());
+    assert!(tree.root().first_child().unwrap().has_siblings());
+}
+
+#[test]
+fn has_children() {
+    let tree = tree!('a' => { 'b', 'c' });
+    assert!(tree.root().has_children());
+    assert!(!tree.root().first_child().unwrap().has_children());
+}
+
+#[test]
+fn clone() {
+    let tree = tree!('a');
+    let one = tree.root();
+    let two = one;
+    assert_eq!(one, two);
+}
+
+#[test]
+fn eq() {
+    let tree = tree!('a');
+    assert_eq!(tree.root(), tree.root());
+}
+
+#[test]
+#[should_panic]
+fn neq() {
+    let tree = tree!('a' => { 'b', 'c' });
+    assert_eq!(tree.root(), tree.root().first_child().unwrap());
+}
+
+#[test]
+#[should_panic]
+fn neq_tree() {
+    let one = tree!('a');
+    let two = one.clone();
+    assert_eq!(one.root(), two.root());
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/serde.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/serde.rs
new file mode 100644
index 000000000000..0e0deee2d485
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/serde.rs
@@ -0,0 +1,96 @@
+#![cfg(feature = "serde")]
+
+use ego_tree::tree;
+use serde_test::{assert_tokens, Token};
+
+#[test]
+fn test_internal_serde_repr_trivial() {
+    let tree = tree!("a");
+
+    assert_tokens(
+        &tree,
+        &[
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("a"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
+#[test]
+fn test_internal_serde_repr() {
+    let tree = tree!("a" => {"b", "c" => {"d", "e"}, "f"});
+
+    assert_tokens(
+        &tree,
+        &[
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("a"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(3) },
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("b"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+            Token::StructEnd,
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("c"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(2) },
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("d"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+            Token::StructEnd,
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("e"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+            Token::StructEnd,
+            Token::SeqEnd,
+            Token::StructEnd,
+            Token::Struct {
+                name: "Node",
+                len: 2,
+            },
+            Token::BorrowedStr("value"),
+            Token::BorrowedStr("f"),
+            Token::BorrowedStr("children"),
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+            Token::StructEnd,
+            Token::SeqEnd,
+            Token::StructEnd,
+        ],
+    );
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/sort.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/sort.rs
new file mode 100644
index 000000000000..c0eb41e03469
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/sort.rs
@@ -0,0 +1,91 @@
+use std::assert_eq;
+
+use ego_tree::tree;
+
+#[test]
+fn sort() {
+    let mut tree = tree!('a' => { 'd' => { 'e', 'f' }, 'c',  'b' });
+    tree.root_mut().sort();
+    assert_eq!(
+        vec![&'b', &'c', &'d'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+    assert_eq!(
+        tree.to_string(),
+        tree!('a' => { 'b', 'c',  'd' => { 'e', 'f' } }).to_string()
+    );
+}
+
+#[test]
+fn sort_by() {
+    let mut tree = tree!('a' => { 'c', 'd', 'b' });
+    tree.root_mut().sort_by(|a, b| b.value().cmp(a.value()));
+    assert_eq!(
+        vec![&'d', &'c', &'b'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+
+    let mut tree = tree!('a' => { 'c','d', 'e', 'b' });
+    tree.root_mut().sort_by(|a, b| b.value().cmp(a.value()));
+    assert_eq!(
+        vec![&'e', &'d', &'c', &'b'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+}
+
+#[test]
+fn sort_by_key() {
+    let mut tree = tree!("1a" => { "2b", "4c", "3d" });
+    tree.root_mut()
+        .sort_by_key(|a| a.value().split_at(1).0.parse::<i32>().unwrap());
+    assert_eq!(
+        vec!["2b", "3d", "4c"],
+        tree.root()
+            .children()
+            .map(|n| *n.value())
+            .collect::<Vec<_>>(),
+    );
+}
+
+#[test]
+fn sort_id() {
+    let mut tree = tree!('a' => { 'd', 'c', 'b' });
+    tree.root_mut().sort();
+    assert_ne!(
+        vec![&'d', &'c', &'b'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+    tree.root_mut().sort_by_key(|n| n.id());
+    assert_eq!(
+        vec![&'d', &'c', &'b'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+}
+
+#[test]
+fn sort_by_id() {
+    let mut tree = tree!('a' => { 'd', 'b', 'c' });
+    tree.root_mut().sort_by(|a, b| b.id().cmp(&a.id()));
+    assert_eq!(
+        vec![&'c', &'b', &'d'],
+        tree.root()
+            .children()
+            .map(|n| n.value())
+            .collect::<Vec<_>>(),
+    );
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/subtree.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/subtree.rs
new file mode 100644
index 000000000000..30a279d22994
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/subtree.rs
@@ -0,0 +1,35 @@
+use ego_tree::tree;
+
+#[test]
+fn prepend_subtree() {
+    let mut tree = tree!('a' => { 'b', 'c' => { 'd', 'e' } });
+    let node_id = tree.root().first_child().unwrap().id();
+    let mut node = tree.get_mut(node_id).unwrap();
+    assert_eq!(node.value(), &'b');
+
+    let subtree = tree!('f' => { 'g', 'h' => { 'i', 'j' } });
+    let mut root_subtree = node.prepend_subtree(subtree);
+    assert_eq!(root_subtree.parent().unwrap().value(), &'b');
+    assert_eq!(
+        root_subtree.parent().unwrap().parent().unwrap().value(),
+        &'a'
+    );
+
+    let new_tree =
+        tree!('a' => { 'b' => { 'f' => { 'g', 'h' => { 'i', 'j' } } }, 'c' => { 'd', 'e' } });
+    assert_eq!(format!("{:#?}", tree), format!("{:#?}", new_tree));
+}
+
+#[test]
+fn append_subtree() {
+    let mut tree = tree!('a' => { 'b', 'c' });
+    let mut node = tree.root_mut();
+    assert_eq!(node.value(), &'a');
+
+    let subtree = tree!('d' => { 'e', 'f' });
+    let mut root_subtree = node.append_subtree(subtree);
+    assert_eq!(root_subtree.parent().unwrap().value(), &'a');
+
+    let new_tree = tree!('a' => { 'b', 'c', 'd' => { 'e', 'f' } });
+    assert_eq!(format!("{:#?}", tree), format!("{:#?}", new_tree));
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/tree.rs b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/tree.rs
new file mode 100644
index 000000000000..cb2878032b25
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/tests/tree.rs
@@ -0,0 +1,240 @@
+use ego_tree::{tree, Tree};
+
+#[test]
+fn new() {
+    let tree = Tree::new('a');
+    let root = tree.root();
+    assert_eq!(&'a', root.value());
+    assert_eq!(None, root.parent());
+    assert_eq!(None, root.prev_sibling());
+    assert_eq!(None, root.next_sibling());
+    assert_eq!(None, root.first_child());
+    assert_eq!(None, root.last_child());
+}
+
+#[test]
+fn root() {
+    let tree = Tree::new('a');
+    assert_eq!(&'a', tree.root().value());
+}
+
+#[test]
+fn root_mut() {
+    let mut tree = Tree::new('a');
+    assert_eq!(&'a', tree.root_mut().value());
+}
+
+#[test]
+fn orphan() {
+    let mut tree = Tree::new('a');
+    let mut orphan = tree.orphan('b');
+    assert_eq!(&'b', orphan.value());
+    assert!(orphan.parent().is_none());
+}
+
+#[test]
+fn get() {
+    let tree = Tree::new('a');
+    let id = tree.root().id();
+    assert_eq!(Some(tree.root()), tree.get(id));
+}
+
+#[test]
+fn get_mut() {
+    let mut tree = Tree::new('a');
+    let id = tree.root().id();
+    assert_eq!(Some('a'), tree.get_mut(id).map(|mut n| *n.value()));
+}
+
+#[test]
+fn clone() {
+    let one = Tree::new('a');
+    let two = one.clone();
+    assert_eq!(one, two);
+}
+
+#[test]
+fn eq() {
+    let one = Tree::new('a');
+    let two = Tree::new('a');
+    assert_eq!(one, two);
+}
+
+#[test]
+#[should_panic]
+fn neq() {
+    let one = Tree::new('a');
+    let two = Tree::new('b');
+    assert_eq!(one, two);
+}
+
+#[test]
+fn insert_id_after() {
+    let mut tree = tree! {
+        "root" => {
+            "a" => {
+                "child 1",
+            },
+            "b" => {
+                "child 2",
+            },
+        }
+    };
+
+    let a = tree.root().first_child().unwrap().id();
+    let b = tree.root().last_child().unwrap().id();
+
+    assert_eq!(2, tree.root().children().count());
+    assert_eq!(1, tree.get(a).unwrap().children().count());
+    assert_eq!(1, tree.get(b).unwrap().children().count());
+
+    let child_1 = tree.get(a).unwrap().first_child().unwrap().id();
+    tree.get_mut(b).unwrap().insert_id_after(child_1);
+
+    assert_eq!(
+        0,
+        tree.get(a).unwrap().children().count(),
+        "child 1 should be moved from a"
+    );
+    assert_eq!(
+        1,
+        tree.get(b).unwrap().children().count(),
+        "b should be unchanged"
+    );
+    assert_eq!(
+        child_1,
+        tree.root().last_child().unwrap().id(),
+        "child 1 should be last child of root"
+    );
+    assert_eq!(3, tree.root().children().count());
+}
+
+#[test]
+fn insert_id_before() {
+    let mut tree = tree! {
+        "root" => {
+            "a" => {
+                "child 1",
+            },
+            "b" => {
+                "child 2",
+            },
+        }
+    };
+
+    let a = tree.root().first_child().unwrap().id();
+    let b = tree.root().last_child().unwrap().id();
+
+    assert_eq!(2, tree.root().children().count());
+    assert_eq!(1, tree.get(a).unwrap().children().count());
+    assert_eq!(1, tree.get(b).unwrap().children().count());
+
+    let child_1 = tree.get(a).unwrap().first_child().unwrap().id();
+    tree.get_mut(b).unwrap().insert_id_before(child_1);
+
+    assert_eq!(
+        0,
+        tree.get(a).unwrap().children().count(),
+        "child 1 should be moved from a"
+    );
+    assert_eq!(
+        1,
+        tree.get(b).unwrap().children().count(),
+        "b should be unchanged"
+    );
+    assert_eq!(
+        b,
+        tree.root().last_child().unwrap().id(),
+        "b should be last child of root"
+    );
+    assert_eq!(
+        child_1,
+        tree.get(b).unwrap().prev_sibling().unwrap().id(),
+        "child 1 should be between a and b"
+    );
+    assert_eq!(3, tree.root().children().count());
+}
+
+#[test]
+fn test_map_values() {
+    let str_tree = tree! {
+        "root" => {
+            "a" => {
+                "child 1",
+            },
+            "b" => {
+                "child 2",
+            },
+        }
+    };
+
+    let identity_mapped_tree = str_tree.clone().map(|value| value);
+
+    // If we pass the identity function to `.map_values()`,
+    // then we expect the tree to effectively remain untouched:
+    assert_eq!(str_tree, identity_mapped_tree);
+
+    let string_tree = str_tree.clone().map(|value| value.to_owned());
+
+    // A `&str` will produce the same output for `.to_string()` as its equivalent `String`,
+    // so the output of `.to_string()` should match for corresponding trees as well:
+    assert_eq!(str_tree.to_string(), string_tree.to_string());
+}
+
+#[test]
+fn test_map_value_refs() {
+    let str_tree = tree! {
+        "root" => {
+            "a" => {
+                "child 1",
+            },
+            "b" => {
+                "child 2",
+            },
+        }
+    };
+
+    let identity_mapped_tree = str_tree.map_ref(|&value| value);
+
+    // If we pass the identity function to `.map_values()`,
+    // then we expect the tree to effectively remain untouched:
+    assert_eq!(str_tree, identity_mapped_tree);
+
+    let string_tree = str_tree.map_ref(|&value| value.to_owned());
+
+    // A `&str` will produce the same output for `.to_string()` as its equivalent `String`,
+    // so the output of `.to_string()` should match for corresponding trees as well:
+    assert_eq!(str_tree.to_string(), string_tree.to_string());
+}
+
+#[test]
+fn test_display() {
+    let tree = tree! {
+        "root" => {
+            "a" => {
+                "child 1",
+            },
+            "b" => {
+                "child 2",
+            },
+        }
+    };
+
+    let repr = format!("{tree}");
+    let expected = "root\n├── a\n│   └── child 1\n└── b\n    └── child 2\n";
+
+    assert_eq!(repr, expected);
+
+    let tree = tree! {
+        "root" => {
+            "a", "b" => {
+                "x", "y"
+            }, "c"
+        }
+    };
+
+    let repr = format!("{tree}");
+    let expected = "root\n├── a\n├── b\n│   ├── x\n│   └── y\n└── c\n";
+
+    assert_eq!(repr, expected);
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo_vcs_info.json
new file mode 100644
index 000000000000..8e9a38a0f4c4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.cargo_vcs_info.json
@@ -0,0 +1,5 @@
+{
+  "git": {
+    "sha1": "be919b8323f57ba238ea9cd6e68190029809e278"
+  }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.github/workflows/main.yml b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.github/workflows/main.yml
new file mode 100644
index 000000000000..2abb4bd62cfa
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.github/workflows/main.yml
@@ -0,0 +1,15 @@
+name: CI
+on: [push, pull_request]
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust: [stable, beta, nightly]
+    steps:
+    - uses: actions/checkout@master
+    - name: Install Rust
+      run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
+    - run: cargo test
+    - run: cargo doc
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.gitignore b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.gitignore
new file mode 100644
index 000000000000..f0d90b95b501
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/.gitignore
@@ -0,0 +1,6 @@
+# Cargo
+/target
+/Cargo.lock
+
+#IDE
+.vscode
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml
new file mode 100644
index 000000000000..db224fcf5a5c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml
@@ -0,0 +1,40 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "getopts"
+version = "0.2.21"
+authors = ["The Rust Project Developers"]
+description = "getopts-like option parsing.\n"
+homepage = "https://github.com/rust-lang/getopts"
+documentation = "https://doc.rust-lang.org/getopts"
+readme = "README.md"
+categories = ["command-line-interface"]
+license = "MIT/Apache-2.0"
+repository = "https://github.com/rust-lang/getopts"
+[dependencies.core]
+version = "1.0"
+optional = true
+package = "rustc-std-workspace-core"
+
+[dependencies.std]
+version = "1.0"
+optional = true
+package = "rustc-std-workspace-std"
+
+[dependencies.unicode-width]
+version = "0.1.5"
+[dev-dependencies.log]
+version = "0.4"
+
+[features]
+rustc-dep-of-std = ["unicode-width/rustc-dep-of-std", "std", "core"]
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml.orig
new file mode 100644
index 000000000000..b55900245e8f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/Cargo.toml.orig
@@ -0,0 +1,25 @@
+[package]
+
+name = "getopts"
+version = "0.2.21" # don't forget to update html_root_url
+authors = ["The Rust Project Developers"]
+license = "MIT/Apache-2.0"
+readme = "README.md"
+repository = "https://github.com/rust-lang/getopts"
+documentation = "https://doc.rust-lang.org/getopts"
+homepage = "https://github.com/rust-lang/getopts"
+description = """
+getopts-like option parsing.
+"""
+categories = ["command-line-interface"]
+
+[dependencies]
+unicode-width = "0.1.5"
+std = { version = "1.0", package = "rustc-std-workspace-std", optional = true }
+core = { version = "1.0", package = "rustc-std-workspace-core", optional = true }
+
+[dev-dependencies]
+log = "0.4"
+
+[features]
+rustc-dep-of-std = ['unicode-width/rustc-dep-of-std', 'std', 'core']
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-APACHE b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-APACHE
new file mode 100644
index 000000000000..16fe87b06e80
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+   "License" shall mean the terms and conditions for use, reproduction,
+   and distribution as defined by Sections 1 through 9 of this document.
+
+   "Licensor" shall mean the copyright owner or entity authorized by
+   the copyright owner that is granting the License.
+
+   "Legal Entity" shall mean the union of the acting entity and all
+   other entities that control, are controlled by, or are under common
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+   direction or management of such entity, whether by contract or
+   otherwise, or (ii) ownership of fifty percent (50%) or more of the
+   outstanding shares, or (iii) beneficial ownership of such entity.
+
+   "You" (or "Your") shall mean an individual or Legal Entity
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+
+   "Work" shall mean the work of authorship, whether in Source or
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+
+   "Derivative Works" shall mean any work, whether in Source or Object
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+   editorial revisions, annotations, elaborations, or other modifications
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+   of this License, Derivative Works shall not include works that remain
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+   "Contribution" shall mean any work of authorship, including
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+5. Submission of Contributions. Unless You explicitly state otherwise,
+   any Contribution intentionally submitted for inclusion in the Work
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+6. Trademarks. This License does not grant permission to use the trade
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+   file or class name and description of purpose be included on the
+   same "printed page" as the copyright notice for easier
+   identification within third-party archives.
+
+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-MIT b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-MIT
new file mode 100644
index 000000000000..39d4bdb5acd3
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2014 The Rust Project Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/README.md b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/README.md
new file mode 100644
index 000000000000..065a05638da9
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/README.md
@@ -0,0 +1,15 @@
+getopts
+===
+
+A Rust library for option parsing for CLI utilities.
+
+[Documentation](https://docs.rs/getopts)
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+getopts = "0.2"
+```
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs
new file mode 100644
index 000000000000..fd45b9508a7c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs
@@ -0,0 +1,1046 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// ignore-lexer-test FIXME #15677
+
+//! Simple getopt alternative.
+//!
+//! Construct a vector of options, either by using `reqopt`, `optopt`, and
+//! `optflag` or by building them from components yourself, and pass them to
+//! `getopts`, along with a vector of actual arguments (not including
+//! `argv[0]`). You'll either get a failure code back, or a match. You'll have
+//! to verify whether the amount of 'free' arguments in the match is what you
+//! expect. Use `opt_*` accessors to get argument values out of the matches
+//! object.
+//!
+//! Single-character options are expected to appear on the command line with a
+//! single preceding dash; multiple-character options are expected to be
+//! proceeded by two dashes. Options that expect an argument accept their
+//! argument following either a space or an equals sign. Single-character
+//! options don't require the space.
+//!
+//! # Usage
+//!
+//! This crate is [on crates.io](https://crates.io/crates/getopts) and can be
+//! used by adding `getopts` to the dependencies in your project's `Cargo.toml`.
+//!
+//! ```toml
+//! [dependencies]
+//! getopts = "0.2"
+//! ```
+//!
+//! and this to your crate root:
+//!
+//! ```rust
+//! extern crate getopts;
+//! ```
+//!
+//! # Example
+//!
+//! The following example shows simple command line parsing for an application
+//! that requires an input file to be specified, accepts an optional output file
+//! name following `-o`, and accepts both `-h` and `--help` as optional flags.
+//!
+//! ```{.rust}
+//! extern crate getopts;
+//! use getopts::Options;
+//! use std::env;
+//!
+//! fn do_work(inp: &str, out: Option<String>) {
+//!     println!("{}", inp);
+//!     match out {
+//!         Some(x) => println!("{}", x),
+//!         None => println!("No Output"),
+//!     }
+//! }
+//!
+//! fn print_usage(program: &str, opts: Options) {
+//!     let brief = format!("Usage: {} FILE [options]", program);
+//!     print!("{}", opts.usage(&brief));
+//! }
+//!
+//! fn main() {
+//!     let args: Vec<String> = env::args().collect();
+//!     let program = args[0].clone();
+//!
+//!     let mut opts = Options::new();
+//!     opts.optopt("o", "", "set output file name", "NAME");
+//!     opts.optflag("h", "help", "print this help menu");
+//!     let matches = match opts.parse(&args[1..]) {
+//!         Ok(m) => { m }
+//!         Err(f) => { panic!(f.to_string()) }
+//!     };
+//!     if matches.opt_present("h") {
+//!         print_usage(&program, opts);
+//!         return;
+//!     }
+//!     let output = matches.opt_str("o");
+//!     let input = if !matches.free.is_empty() {
+//!         matches.free[0].clone()
+//!     } else {
+//!         print_usage(&program, opts);
+//!         return;
+//!     };
+//!     do_work(&input, output);
+//! }
+//! ```
+
+#![doc(
+    html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
+    html_favicon_url = "https://www.rust-lang.org/favicon.ico",
+    html_root_url = "https://docs.rs/getopts/0.2.20"
+)]
+#![deny(missing_docs)]
+#![cfg_attr(test, deny(warnings))]
+
+#[cfg(test)]
+#[macro_use]
+extern crate log;
+extern crate unicode_width;
+
+use self::Fail::*;
+use self::HasArg::*;
+use self::Name::*;
+use self::Occur::*;
+use self::Optval::*;
+
+use std::error::Error;
+use std::ffi::OsStr;
+use std::fmt;
+use std::iter::{repeat, IntoIterator};
+use std::result;
+use std::str::FromStr;
+
+use unicode_width::UnicodeWidthStr;
+
+#[cfg(test)]
+mod tests;
+
+/// A description of the options that a program can handle.
+pub struct Options {
+    grps: Vec<OptGroup>,
+    parsing_style: ParsingStyle,
+    long_only: bool,
+}
+
+impl Default for Options {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Options {
+    /// Create a blank set of options.
+    pub fn new() -> Options {
+        Options {
+            grps: Vec::new(),
+            parsing_style: ParsingStyle::FloatingFrees,
+            long_only: false,
+        }
+    }
+
+    /// Set the parsing style.
+    pub fn parsing_style(&mut self, style: ParsingStyle) -> &mut Options {
+        self.parsing_style = style;
+        self
+    }
+
+    /// Set or clear "long options only" mode.
+    ///
+    /// In "long options only" mode, short options cannot be clustered
+    /// together, and long options can be given with either a single
+    /// "-" or the customary "--".  This mode also changes the meaning
+    /// of "-a=b"; in the ordinary mode this will parse a short option
+    /// "-a" with argument "=b"; whereas in long-options-only mode the
+    /// argument will be simply "b".
+    pub fn long_only(&mut self, long_only: bool) -> &mut Options {
+        self.long_only = long_only;
+        self
+    }
+
+    /// Create a generic option group, stating all parameters explicitly.
+    pub fn opt(
+        &mut self,
+        short_name: &str,
+        long_name: &str,
+        desc: &str,
+        hint: &str,
+        hasarg: HasArg,
+        occur: Occur,
+    ) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: hint.to_string(),
+            desc: desc.to_string(),
+            hasarg,
+            occur,
+        });
+        self
+    }
+
+    /// Create a long option that is optional and does not take an argument.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    pub fn optflag(&mut self, short_name: &str, long_name: &str, desc: &str) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: "".to_string(),
+            desc: desc.to_string(),
+            hasarg: No,
+            occur: Optional,
+        });
+        self
+    }
+
+    /// Create a long option that can occur more than once and does not
+    /// take an argument.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    pub fn optflagmulti(&mut self, short_name: &str, long_name: &str, desc: &str) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: "".to_string(),
+            desc: desc.to_string(),
+            hasarg: No,
+            occur: Multi,
+        });
+        self
+    }
+
+    /// Create a long option that is optional and takes an optional argument.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    /// * `hint` - Hint that is used in place of the argument in the usage help,
+    ///   e.g. `"FILE"` for a `-o FILE` option
+    pub fn optflagopt(
+        &mut self,
+        short_name: &str,
+        long_name: &str,
+        desc: &str,
+        hint: &str,
+    ) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: hint.to_string(),
+            desc: desc.to_string(),
+            hasarg: Maybe,
+            occur: Optional,
+        });
+        self
+    }
+
+    /// Create a long option that is optional, takes an argument, and may occur
+    /// multiple times.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    /// * `hint` - Hint that is used in place of the argument in the usage help,
+    ///   e.g. `"FILE"` for a `-o FILE` option
+    pub fn optmulti(
+        &mut self,
+        short_name: &str,
+        long_name: &str,
+        desc: &str,
+        hint: &str,
+    ) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: hint.to_string(),
+            desc: desc.to_string(),
+            hasarg: Yes,
+            occur: Multi,
+        });
+        self
+    }
+
+    /// Create a long option that is optional and takes an argument.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    /// * `hint` - Hint that is used in place of the argument in the usage help,
+    ///   e.g. `"FILE"` for a `-o FILE` option
+    pub fn optopt(
+        &mut self,
+        short_name: &str,
+        long_name: &str,
+        desc: &str,
+        hint: &str,
+    ) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: hint.to_string(),
+            desc: desc.to_string(),
+            hasarg: Yes,
+            occur: Optional,
+        });
+        self
+    }
+
+    /// Create a long option that is required and takes an argument.
+    ///
+    /// * `short_name` - e.g. `"h"` for a `-h` option, or `""` for none
+    /// * `long_name` - e.g. `"help"` for a `--help` option, or `""` for none
+    /// * `desc` - Description for usage help
+    /// * `hint` - Hint that is used in place of the argument in the usage help,
+    ///   e.g. `"FILE"` for a `-o FILE` option
+    pub fn reqopt(
+        &mut self,
+        short_name: &str,
+        long_name: &str,
+        desc: &str,
+        hint: &str,
+    ) -> &mut Options {
+        validate_names(short_name, long_name);
+        self.grps.push(OptGroup {
+            short_name: short_name.to_string(),
+            long_name: long_name.to_string(),
+            hint: hint.to_string(),
+            desc: desc.to_string(),
+            hasarg: Yes,
+            occur: Req,
+        });
+        self
+    }
+
+    /// Parse command line arguments according to the provided options.
+    ///
+    /// On success returns `Ok(Matches)`. Use methods such as `opt_present`
+    /// `opt_str`, etc. to interrogate results.
+    /// # Panics
+    ///
+    /// Returns `Err(Fail)` on failure: use the `Debug` implementation of `Fail`
+    /// to display information about it.
+    pub fn parse<C: IntoIterator>(&self, args: C) -> Result
+    where
+        C::Item: AsRef<OsStr>,
+    {
+        let opts: Vec<Opt> = self.grps.iter().map(|x| x.long_to_short()).collect();
+
+        let mut vals = (0..opts.len())
+            .map(|_| Vec::new())
+            .collect::<Vec<Vec<(usize, Optval)>>>();
+        let mut free: Vec<String> = Vec::new();
+        let args = args
+            .into_iter()
+            .map(|i| {
+                i.as_ref()
+                    .to_str()
+                    .ok_or_else(|| Fail::UnrecognizedOption(format!("{:?}", i.as_ref())))
+                    .map(|s| s.to_owned())
+            })
+            .collect::<::std::result::Result<Vec<_>, _>>()?;
+        let mut args = args.into_iter().peekable();
+        let mut arg_pos = 0;
+        while let Some(cur) = args.next() {
+            if !is_arg(&cur) {
+                free.push(cur);
+                match self.parsing_style {
+                    ParsingStyle::FloatingFrees => {}
+                    ParsingStyle::StopAtFirstFree => {
+                        free.extend(args);
+                        break;
+                    }
+                }
+            } else if cur == "--" {
+                free.extend(args);
+                break;
+            } else {
+                let mut names;
+                let mut i_arg = None;
+                let mut was_long = true;
+                if cur.as_bytes()[1] == b'-' || self.long_only {
+                    let tail = if cur.as_bytes()[1] == b'-' {
+                        &cur[2..]
+                    } else {
+                        assert!(self.long_only);
+                        &cur[1..]
+                    };
+                    let mut parts = tail.splitn(2, '=');
+                    names = vec![Name::from_str(parts.next().unwrap())];
+                    if let Some(rest) = parts.next() {
+                        i_arg = Some(rest.to_string());
+                    }
+                } else {
+                    was_long = false;
+                    names = Vec::new();
+                    for (j, ch) in cur.char_indices().skip(1) {
+                        let opt = Short(ch);
+
+                        /* In a series of potential options (eg. -aheJ), if we
+                           see one which takes an argument, we assume all
+                           subsequent characters make up the argument. This
+                           allows options such as -L/usr/local/lib/foo to be
+                           interpreted correctly
+                        */
+
+                        let opt_id = match find_opt(&opts, &opt) {
+                            Some(id) => id,
+                            None => return Err(UnrecognizedOption(opt.to_string())),
+                        };
+
+                        names.push(opt);
+
+                        let arg_follows = match opts[opt_id].hasarg {
+                            Yes | Maybe => true,
+                            No => false,
+                        };
+
+                        if arg_follows {
+                            let next = j + ch.len_utf8();
+                            if next < cur.len() {
+                                i_arg = Some(cur[next..].to_string());
+                                break;
+                            }
+                        }
+                    }
+                }
+                let mut name_pos = 0;
+                for nm in names.iter() {
+                    name_pos += 1;
+                    let optid = match find_opt(&opts, &nm) {
+                        Some(id) => id,
+                        None => return Err(UnrecognizedOption(nm.to_string())),
+                    };
+                    match opts[optid].hasarg {
+                        No => {
+                            if name_pos == names.len() && i_arg.is_some() {
+                                return Err(UnexpectedArgument(nm.to_string()));
+                            }
+                            vals[optid].push((arg_pos, Given));
+                        }
+                        Maybe => {
+                            // Note that here we do not handle `--arg value`.
+                            // This matches GNU getopt behavior; but also
+                            // makes sense, because if this were accepted,
+                            // then users could only write a "Maybe" long
+                            // option at the end of the arguments when
+                            // FloatingFrees is in use.
+                            if let Some(i_arg) = i_arg.take() {
+                                vals[optid].push((arg_pos, Val(i_arg)));
+                            } else if was_long
+                                || name_pos < names.len()
+                                || args.peek().map_or(true, |n| is_arg(&n))
+                            {
+                                vals[optid].push((arg_pos, Given));
+                            } else {
+                                vals[optid].push((arg_pos, Val(args.next().unwrap())));
+                            }
+                        }
+                        Yes => {
+                            if let Some(i_arg) = i_arg.take() {
+                                vals[optid].push((arg_pos, Val(i_arg)));
+                            } else if let Some(n) = args.next() {
+                                vals[optid].push((arg_pos, Val(n)));
+                            } else {
+                                return Err(ArgumentMissing(nm.to_string()));
+                            }
+                        }
+                    }
+                }
+            }
+            arg_pos += 1;
+        }
+        debug_assert_eq!(vals.len(), opts.len());
+        for (vals, opt) in vals.iter().zip(opts.iter()) {
+            if opt.occur == Req && vals.is_empty() {
+                return Err(OptionMissing(opt.name.to_string()));
+            }
+            if opt.occur != Multi && vals.len() > 1 {
+                return Err(OptionDuplicated(opt.name.to_string()));
+            }
+        }
+        Ok(Matches { opts, vals, free })
+    }
+
+    /// Derive a short one-line usage summary from a set of long options.
+    pub fn short_usage(&self, program_name: &str) -> String {
+        let mut line = format!("Usage: {} ", program_name);
+        line.push_str(
+            &self
+                .grps
+                .iter()
+                .map(format_option)
+                .collect::<Vec<String>>()
+                .join(" "),
+        );
+        line
+    }
+
+    /// Derive a formatted message from a set of options.
+    pub fn usage(&self, brief: &str) -> String {
+        self.usage_with_format(|opts| {
+            format!(
+                "{}\n\nOptions:\n{}\n",
+                brief,
+                opts.collect::<Vec<String>>().join("\n")
+            )
+        })
+    }
+
+    /// Derive a custom formatted message from a set of options. The formatted options provided to
+    /// a closure as an iterator.
+    pub fn usage_with_format<F: FnMut(&mut dyn Iterator<Item = String>) -> String>(
+        &self,
+        mut formatter: F,
+    ) -> String {
+        formatter(&mut self.usage_items())
+    }
+
+    /// Derive usage items from a set of options.
+    fn usage_items<'a>(&'a self) -> Box<dyn Iterator<Item = String> + 'a> {
+        let desc_sep = format!("\n{}", repeat(" ").take(24).collect::<String>());
+
+        let any_short = self.grps.iter().any(|optref| !optref.short_name.is_empty());
+
+        let rows = self.grps.iter().map(move |optref| {
+            let OptGroup {
+                short_name,
+                long_name,
+                hint,
+                desc,
+                hasarg,
+                ..
+            } = (*optref).clone();
+
+            let mut row = "    ".to_string();
+
+            // short option
+            match short_name.width() {
+                0 => {
+                    if any_short {
+                        row.push_str("    ");
+                    }
+                }
+                1 => {
+                    row.push('-');
+                    row.push_str(&short_name);
+                    if long_name.width() > 0 {
+                        row.push_str(", ");
+                    } else {
+                        // Only a single space here, so that any
+                        // argument is printed in the correct spot.
+                        row.push(' ');
+                    }
+                }
+                // FIXME: refer issue #7.
+                _ => panic!("the short name should only be 1 ascii char long"),
+            }
+
+            // long option
+            match long_name.width() {
+                0 => {}
+                _ => {
+                    row.push_str(if self.long_only { "-" } else { "--" });
+                    row.push_str(&long_name);
+                    row.push(' ');
+                }
+            }
+
+            // arg
+            match hasarg {
+                No => {}
+                Yes => row.push_str(&hint),
+                Maybe => {
+                    row.push('[');
+                    row.push_str(&hint);
+                    row.push(']');
+                }
+            }
+
+            let rowlen = row.width();
+            if rowlen < 24 {
+                for _ in 0..24 - rowlen {
+                    row.push(' ');
+                }
+            } else {
+                row.push_str(&desc_sep)
+            }
+
+            let desc_rows = each_split_within(&desc, 54);
+            row.push_str(&desc_rows.join(&desc_sep));
+
+            row
+        });
+
+        Box::new(rows)
+    }
+}
+
+fn validate_names(short_name: &str, long_name: &str) {
+    let len = short_name.len();
+    assert!(
+        len == 1 || len == 0,
+        "the short_name (first argument) should be a single character, \
+         or an empty string for none"
+    );
+    let len = long_name.len();
+    assert!(
+        len == 0 || len > 1,
+        "the long_name (second argument) should be longer than a single \
+         character, or an empty string for none"
+    );
+}
+
+/// What parsing style to use when parsing arguments.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub enum ParsingStyle {
+    /// Flags and "free" arguments can be freely inter-mixed.
+    FloatingFrees,
+    /// As soon as a "free" argument (i.e. non-flag) is encountered, stop
+    /// considering any remaining arguments as flags.
+    StopAtFirstFree,
+}
+
+/// Name of an option. Either a string or a single char.
+#[derive(Clone, Debug, PartialEq, Eq)]
+enum Name {
+    /// A string representing the long name of an option.
+    /// For example: "help"
+    Long(String),
+    /// A char representing the short name of an option.
+    /// For example: 'h'
+    Short(char),
+}
+
+/// Describes whether an option has an argument.
+#[derive(Clone, Debug, Copy, PartialEq, Eq)]
+pub enum HasArg {
+    /// The option requires an argument.
+    Yes,
+    /// The option takes no argument.
+    No,
+    /// The option argument is optional.
+    Maybe,
+}
+
+/// Describes how often an option may occur.
+#[derive(Clone, Debug, Copy, PartialEq, Eq)]
+pub enum Occur {
+    /// The option occurs once.
+    Req,
+    /// The option occurs at most once.
+    Optional,
+    /// The option occurs zero or more times.
+    Multi,
+}
+
+/// A description of a possible option.
+#[derive(Clone, Debug, PartialEq, Eq)]
+struct Opt {
+    /// Name of the option
+    name: Name,
+    /// Whether it has an argument
+    hasarg: HasArg,
+    /// How often it can occur
+    occur: Occur,
+    /// Which options it aliases
+    aliases: Vec<Opt>,
+}
+
+/// One group of options, e.g., both `-h` and `--help`, along with
+/// their shared description and properties.
+#[derive(Clone, PartialEq, Eq)]
+struct OptGroup {
+    /// Short name of the option, e.g. `h` for a `-h` option
+    short_name: String,
+    /// Long name of the option, e.g. `help` for a `--help` option
+    long_name: String,
+    /// Hint for argument, e.g. `FILE` for a `-o FILE` option
+    hint: String,
+    /// Description for usage help text
+    desc: String,
+    /// Whether option has an argument
+    hasarg: HasArg,
+    /// How often it can occur
+    occur: Occur,
+}
+
+/// Describes whether an option is given at all or has a value.
+#[derive(Clone, Debug, PartialEq, Eq)]
+enum Optval {
+    Val(String),
+    Given,
+}
+
+/// The result of checking command line arguments. Contains a vector
+/// of matches and a vector of free strings.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Matches {
+    /// Options that matched
+    opts: Vec<Opt>,
+    /// Values of the Options that matched and their positions
+    vals: Vec<Vec<(usize, Optval)>>,
+    /// Free string fragments
+    pub free: Vec<String>,
+}
+
+/// The type returned when the command line does not conform to the
+/// expected format. Use the `Debug` implementation to output detailed
+/// information.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Fail {
+    /// The option requires an argument but none was passed.
+    ArgumentMissing(String),
+    /// The passed option is not declared among the possible options.
+    UnrecognizedOption(String),
+    /// A required option is not present.
+    OptionMissing(String),
+    /// A single occurrence option is being used multiple times.
+    OptionDuplicated(String),
+    /// There's an argument being passed to a non-argument option.
+    UnexpectedArgument(String),
+}
+
+impl Error for Fail {
+    fn description(&self) -> &str {
+        match *self {
+            ArgumentMissing(_) => "missing argument",
+            UnrecognizedOption(_) => "unrecognized option",
+            OptionMissing(_) => "missing option",
+            OptionDuplicated(_) => "duplicated option",
+            UnexpectedArgument(_) => "unexpected argument",
+        }
+    }
+}
+
+/// The result of parsing a command line with a set of options.
+pub type Result = result::Result<Matches, Fail>;
+
+impl Name {
+    fn from_str(nm: &str) -> Name {
+        if nm.len() == 1 {
+            Short(nm.as_bytes()[0] as char)
+        } else {
+            Long(nm.to_string())
+        }
+    }
+
+    fn to_string(&self) -> String {
+        match *self {
+            Short(ch) => ch.to_string(),
+            Long(ref s) => s.to_string(),
+        }
+    }
+}
+
+impl OptGroup {
+    /// Translate OptGroup into Opt.
+    /// (Both short and long names correspond to different Opts).
+    fn long_to_short(&self) -> Opt {
+        let OptGroup {
+            short_name,
+            long_name,
+            hasarg,
+            occur,
+            ..
+        } = (*self).clone();
+
+        match (short_name.len(), long_name.len()) {
+            (0, 0) => panic!("this long-format option was given no name"),
+            (0, _) => Opt {
+                name: Long(long_name),
+                hasarg,
+                occur,
+                aliases: Vec::new(),
+            },
+            (1, 0) => Opt {
+                name: Short(short_name.as_bytes()[0] as char),
+                hasarg,
+                occur,
+                aliases: Vec::new(),
+            },
+            (1, _) => Opt {
+                name: Long(long_name),
+                hasarg,
+                occur,
+                aliases: vec![Opt {
+                    name: Short(short_name.as_bytes()[0] as char),
+                    hasarg: hasarg,
+                    occur: occur,
+                    aliases: Vec::new(),
+                }],
+            },
+            (_, _) => panic!("something is wrong with the long-form opt"),
+        }
+    }
+}
+
+impl Matches {
+    fn opt_vals(&self, nm: &str) -> Vec<(usize, Optval)> {
+        match find_opt(&self.opts, &Name::from_str(nm)) {
+            Some(id) => self.vals[id].clone(),
+            None => panic!("No option '{}' defined", nm),
+        }
+    }
+
+    fn opt_val(&self, nm: &str) -> Option<Optval> {
+        self.opt_vals(nm).into_iter().map(|(_, o)| o).next()
+    }
+    /// Returns true if an option was defined
+    pub fn opt_defined(&self, nm: &str) -> bool {
+        find_opt(&self.opts, &Name::from_str(nm)).is_some()
+    }
+
+    /// Returns true if an option was matched.
+    pub fn opt_present(&self, nm: &str) -> bool {
+        !self.opt_vals(nm).is_empty()
+    }
+
+    /// Returns the number of times an option was matched.
+    pub fn opt_count(&self, nm: &str) -> usize {
+        self.opt_vals(nm).len()
+    }
+
+    /// Returns a vector of all the positions in which an option was matched.
+    pub fn opt_positions(&self, nm: &str) -> Vec<usize> {
+        self.opt_vals(nm).into_iter().map(|(pos, _)| pos).collect()
+    }
+
+    /// Returns true if any of several options were matched.
+    pub fn opts_present(&self, names: &[String]) -> bool {
+        names
+            .iter()
+            .any(|nm| match find_opt(&self.opts, &Name::from_str(&nm)) {
+                Some(id) if !self.vals[id].is_empty() => true,
+                _ => false,
+            })
+    }
+
+    /// Returns the string argument supplied to one of several matching options or `None`.
+    pub fn opts_str(&self, names: &[String]) -> Option<String> {
+        names
+            .iter()
+            .filter_map(|nm| match self.opt_val(&nm) {
+                Some(Val(s)) => Some(s),
+                _ => None,
+            })
+            .next()
+    }
+
+    /// Returns a vector of the arguments provided to all matches of the given
+    /// option.
+    ///
+    /// Used when an option accepts multiple values.
+    pub fn opt_strs(&self, nm: &str) -> Vec<String> {
+        self.opt_vals(nm)
+            .into_iter()
+            .filter_map(|(_, v)| match v {
+                Val(s) => Some(s),
+                _ => None,
+            })
+            .collect()
+    }
+
+    /// Returns a vector of the arguments provided to all matches of the given
+    /// option, together with their positions.
+    ///
+    /// Used when an option accepts multiple values.
+    pub fn opt_strs_pos(&self, nm: &str) -> Vec<(usize, String)> {
+        self.opt_vals(nm)
+            .into_iter()
+            .filter_map(|(p, v)| match v {
+                Val(s) => Some((p, s)),
+                _ => None,
+            })
+            .collect()
+    }
+
+    /// Returns the string argument supplied to a matching option or `None`.
+    pub fn opt_str(&self, nm: &str) -> Option<String> {
+        match self.opt_val(nm) {
+            Some(Val(s)) => Some(s),
+            _ => None,
+        }
+    }
+
+    /// Returns the matching string, a default, or `None`.
+    ///
+    /// Returns `None` if the option was not present, `def` if the option was
+    /// present but no argument was provided, and the argument if the option was
+    /// present and an argument was provided.
+    pub fn opt_default(&self, nm: &str, def: &str) -> Option<String> {
+        match self.opt_val(nm) {
+            Some(Val(s)) => Some(s),
+            Some(_) => Some(def.to_string()),
+            None => None,
+        }
+    }
+
+    /// Returns some matching value or `None`.
+    ///
+    /// Similar to opt_str, also converts matching argument using FromStr.
+    pub fn opt_get<T>(&self, nm: &str) -> result::Result<Option<T>, T::Err>
+    where
+        T: FromStr,
+    {
+        match self.opt_val(nm) {
+            Some(Val(s)) => Ok(Some(s.parse()?)),
+            Some(Given) => Ok(None),
+            None => Ok(None),
+        }
+    }
+
+    /// Returns a matching value or default.
+    ///
+    /// Similar to opt_default, except the two differences.
+    /// Instead of returning None when argument was not present, return `def`.
+    /// Instead of returning &str return type T, parsed using str::parse().
+    pub fn opt_get_default<T>(&self, nm: &str, def: T) -> result::Result<T, T::Err>
+    where
+        T: FromStr,
+    {
+        match self.opt_val(nm) {
+            Some(Val(s)) => s.parse(),
+            Some(Given) => Ok(def),
+            None => Ok(def),
+        }
+    }
+}
+
+fn is_arg(arg: &str) -> bool {
+    arg.as_bytes().get(0) == Some(&b'-') && arg.len() > 1
+}
+
+fn find_opt(opts: &[Opt], nm: &Name) -> Option<usize> {
+    // Search main options.
+    let pos = opts.iter().position(|opt| &opt.name == nm);
+    if pos.is_some() {
+        return pos;
+    }
+
+    // Search in aliases.
+    for candidate in opts.iter() {
+        if candidate.aliases.iter().any(|opt| &opt.name == nm) {
+            return opts.iter().position(|opt| opt.name == candidate.name);
+        }
+    }
+
+    None
+}
+
+impl fmt::Display for Fail {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            ArgumentMissing(ref nm) => write!(f, "Argument to option '{}' missing", *nm),
+            UnrecognizedOption(ref nm) => write!(f, "Unrecognized option: '{}'", *nm),
+            OptionMissing(ref nm) => write!(f, "Required option '{}' missing", *nm),
+            OptionDuplicated(ref nm) => write!(f, "Option '{}' given more than once", *nm),
+            UnexpectedArgument(ref nm) => write!(f, "Option '{}' does not take an argument", *nm),
+        }
+    }
+}
+
+fn format_option(opt: &OptGroup) -> String {
+    let mut line = String::new();
+
+    if opt.occur != Req {
+        line.push('[');
+    }
+
+    // Use short_name if possible, but fall back to long_name.
+    if !opt.short_name.is_empty() {
+        line.push('-');
+        line.push_str(&opt.short_name);
+    } else {
+        line.push_str("--");
+        line.push_str(&opt.long_name);
+    }
+
+    if opt.hasarg != No {
+        line.push(' ');
+        if opt.hasarg == Maybe {
+            line.push('[');
+        }
+        line.push_str(&opt.hint);
+        if opt.hasarg == Maybe {
+            line.push(']');
+        }
+    }
+
+    if opt.occur != Req {
+        line.push(']');
+    }
+    if opt.occur == Multi {
+        line.push_str("..");
+    }
+
+    line
+}
+
+/// Splits a string into substrings with possibly internal whitespace,
+/// each of them at most `lim` bytes long, if possible. The substrings
+/// have leading and trailing whitespace removed, and are only cut at
+/// whitespace boundaries.
+fn each_split_within(desc: &str, lim: usize) -> Vec<String> {
+    let mut rows = Vec::new();
+    for line in desc.trim().lines() {
+        let line_chars = line.chars().chain(Some(' '));
+        let words = line_chars
+            .fold((Vec::new(), 0, 0), |(mut words, a, z), c| {
+                let idx = z + c.len_utf8(); // Get the current byte offset
+
+                // If the char is whitespace, advance the word start and maybe push a word
+                if c.is_whitespace() {
+                    if a != z {
+                        words.push(&line[a..z]);
+                    }
+                    (words, idx, idx)
+                }
+                // If the char is not whitespace, continue, retaining the current
+                else {
+                    (words, a, idx)
+                }
+            })
+            .0;
+
+        let mut row = String::new();
+        for word in words.iter() {
+            let sep = if !row.is_empty() { Some(" ") } else { None };
+            let width = row.width() + word.width() + sep.map(UnicodeWidthStr::width).unwrap_or(0);
+
+            if width <= lim {
+                if let Some(sep) = sep {
+                    row.push_str(sep)
+                }
+                row.push_str(word);
+                continue;
+            }
+            if !row.is_empty() {
+                rows.push(row.clone());
+                row.clear();
+            }
+            row.push_str(word);
+        }
+        if !row.is_empty() {
+            rows.push(row);
+        }
+    }
+    rows
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/tests/mod.rs b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/tests/mod.rs
new file mode 100644
index 000000000000..f1fb390987a4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/tests/mod.rs
@@ -0,0 +1,1254 @@
+use super::each_split_within;
+use super::Fail::*;
+use super::{HasArg, Name, Occur, Opt, Options, ParsingStyle};
+
+#[test]
+fn test_split_within() {
+    fn t(s: &str, i: usize, u: &[String]) {
+        let v = each_split_within(&(s.to_string()), i);
+        assert!(v.iter().zip(u.iter()).all(|(a, b)| a == b));
+    }
+    t("", 0, &[]);
+    t("", 15, &[]);
+    t("hello", 15, &["hello".to_string()]);
+    t(
+        "\nMary had a little lamb\nLittle lamb\n",
+        15,
+        &[
+            "Mary had a".to_string(),
+            "little lamb".to_string(),
+            "Little lamb".to_string(),
+        ],
+    );
+    t(
+        "\nMary had a little lamb\nLittle lamb\n",
+        ::std::usize::MAX,
+        &[
+            "Mary had a little lamb".to_string(),
+            "Little lamb".to_string(),
+        ],
+    );
+}
+
+// Tests for reqopt
+#[test]
+fn test_reqopt() {
+    let long_args = vec!["--test=20".to_string()];
+    let mut opts = Options::new();
+    opts.reqopt("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!(m.opt_present("t"));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => {
+            panic!("test_reqopt failed (long arg)");
+        }
+    }
+    let short_args = vec!["-t".to_string(), "20".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert!((m.opt_present("test")));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!((m.opt_present("t")));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => {
+            panic!("test_reqopt failed (short arg)");
+        }
+    }
+}
+
+#[test]
+fn test_reqopt_missing() {
+    let args = vec!["blah".to_string()];
+    match Options::new()
+        .reqopt("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Err(OptionMissing(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_reqopt_no_arg() {
+    let long_args = vec!["--test".to_string()];
+    let mut opts = Options::new();
+    opts.reqopt("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string()];
+    match opts.parse(&short_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_reqopt_multi() {
+    let args = vec!["--test=20".to_string(), "-t".to_string(), "30".to_string()];
+    match Options::new()
+        .reqopt("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Err(OptionDuplicated(_)) => {}
+        _ => panic!(),
+    }
+}
+
+// Tests for optopt
+#[test]
+fn test_optopt() {
+    let long_args = vec!["--test=20".to_string()];
+    let mut opts = Options::new();
+    opts.optopt("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!((m.opt_present("t")));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string(), "20".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert!((m.opt_present("test")));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!((m.opt_present("t")));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optopt_missing() {
+    let args = vec!["blah".to_string()];
+    match Options::new()
+        .optopt("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optopt_no_arg() {
+    let long_args = vec!["--test".to_string()];
+    let mut opts = Options::new();
+    opts.optopt("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string()];
+    match opts.parse(&short_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optopt_multi() {
+    let args = vec!["--test=20".to_string(), "-t".to_string(), "30".to_string()];
+    match Options::new()
+        .optopt("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Err(OptionDuplicated(_)) => {}
+        _ => panic!(),
+    }
+}
+
+// Tests for optflag
+#[test]
+fn test_optflag() {
+    let long_args = vec!["--test".to_string()];
+    let mut opts = Options::new();
+    opts.optflag("t", "test", "testing");
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert!(m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert!(m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflag_missing() {
+    let args = vec!["blah".to_string()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_opt_end() {
+    let args = vec!["--".to_owned(), "-t".to_owned()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+            assert_eq!(m.free.len(), 1);
+            assert_eq!(m.free[0], "-t");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_opt_only_end() {
+    let args = vec!["--".to_owned()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+            assert_eq!(m.free.len(), 0);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflag_long_arg() {
+    let args = vec!["--test=20".to_string()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Err(UnexpectedArgument(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflag_multi() {
+    let args = vec!["--test".to_string(), "-t".to_string()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Err(OptionDuplicated(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflag_short_arg() {
+    let args = vec!["-t".to_string(), "20".to_string()];
+    match Options::new().optflag("t", "test", "testing").parse(&args) {
+        Ok(ref m) => {
+            // The next variable after the flag is just a free argument
+
+            assert!(m.free[0] == "20");
+        }
+        _ => panic!(),
+    }
+}
+
+// Tests for optflagmulti
+#[test]
+fn test_optflagmulti_short1() {
+    let args = vec!["-v".to_string()];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("v"), 1);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflagmulti_short2a() {
+    let args = vec!["-v".to_string(), "-v".to_string()];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("v"), 2);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflagmulti_short2b() {
+    let args = vec!["-vv".to_string()];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("v"), 2);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflagmulti_long1() {
+    let args = vec!["--verbose".to_string()];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("verbose"), 1);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflagmulti_long2() {
+    let args = vec!["--verbose".to_string(), "--verbose".to_string()];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("verbose"), 2);
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optflagmulti_mix() {
+    let args = vec![
+        "--verbose".to_string(),
+        "-v".to_string(),
+        "-vv".to_string(),
+        "verbose".to_string(),
+    ];
+    match Options::new()
+        .optflagmulti("v", "verbose", "verbosity")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert_eq!(m.opt_count("verbose"), 4);
+            assert_eq!(m.opt_count("v"), 4);
+        }
+        _ => panic!(),
+    }
+}
+
+// Tests for optflagopt
+#[test]
+fn test_optflagopt() {
+    let long_args = vec!["--test".to_string()];
+    let mut opts = Options::new();
+    opts.optflagopt("t", "test", "testing", "ARG");
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert!(m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert!(m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string(), "x".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert_eq!(m.opt_str("t").unwrap(), "x");
+            assert_eq!(m.opt_str("test").unwrap(), "x");
+        }
+        _ => panic!(),
+    }
+    let long_args = vec!["--test=x".to_string()];
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert_eq!(m.opt_str("t").unwrap(), "x");
+            assert_eq!(m.opt_str("test").unwrap(), "x");
+        }
+        _ => panic!(),
+    }
+    let long_args = vec!["--test".to_string(), "x".to_string()];
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert_eq!(m.opt_str("t"), None);
+            assert_eq!(m.opt_str("test"), None);
+        }
+        _ => panic!(),
+    }
+    let no_args: Vec<String> = vec![];
+    match opts.parse(&no_args) {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+}
+
+// Tests for optmulti
+#[test]
+fn test_optmulti() {
+    let long_args = vec!["--test=20".to_string()];
+    let mut opts = Options::new();
+    opts.optmulti("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Ok(ref m) => {
+            assert!((m.opt_present("test")));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!((m.opt_present("t")));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string(), "20".to_string()];
+    match opts.parse(&short_args) {
+        Ok(ref m) => {
+            assert!((m.opt_present("test")));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!((m.opt_present("t")));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optmulti_missing() {
+    let args = vec!["blah".to_string()];
+    match Options::new()
+        .optmulti("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert!(!m.opt_present("test"));
+            assert!(!m.opt_present("t"));
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optmulti_no_arg() {
+    let long_args = vec!["--test".to_string()];
+    let mut opts = Options::new();
+    opts.optmulti("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+    let short_args = vec!["-t".to_string()];
+    match opts.parse(&short_args) {
+        Err(ArgumentMissing(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_optmulti_multi() {
+    let args = vec!["--test=20".to_string(), "-t".to_string(), "30".to_string()];
+    match Options::new()
+        .optmulti("t", "test", "testing", "TEST")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert!(m.opt_present("test"));
+            assert_eq!(m.opt_str("test").unwrap(), "20");
+            assert!(m.opt_present("t"));
+            assert_eq!(m.opt_str("t").unwrap(), "20");
+            let pair = m.opt_strs("test");
+            assert!(pair[0] == "20");
+            assert!(pair[1] == "30");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_free_argument_is_hyphen() {
+    let args = vec!["-".to_string()];
+    match Options::new().parse(&args) {
+        Ok(ref m) => {
+            assert_eq!(m.free.len(), 1);
+            assert_eq!(m.free[0], "-");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_unrecognized_option() {
+    let long_args = vec!["--untest".to_string()];
+    let mut opts = Options::new();
+    opts.optmulti("t", "test", "testing", "TEST");
+    match opts.parse(&long_args) {
+        Err(UnrecognizedOption(_)) => {}
+        _ => panic!(),
+    }
+    let short_args = vec!["-u".to_string()];
+    match opts.parse(&short_args) {
+        Err(UnrecognizedOption(_)) => {}
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_combined() {
+    let args = vec![
+        "prog".to_string(),
+        "free1".to_string(),
+        "-s".to_string(),
+        "20".to_string(),
+        "free2".to_string(),
+        "--flag".to_string(),
+        "--long=30".to_string(),
+        "-f".to_string(),
+        "-m".to_string(),
+        "40".to_string(),
+        "-m".to_string(),
+        "50".to_string(),
+        "-n".to_string(),
+        "-A B".to_string(),
+        "-n".to_string(),
+        "-60 70".to_string(),
+    ];
+    match Options::new()
+        .optopt("s", "something", "something", "SOMETHING")
+        .optflag("", "flag", "a flag")
+        .reqopt("", "long", "hi", "LONG")
+        .optflag("f", "", "another flag")
+        .optmulti("m", "", "mmmmmm", "YUM")
+        .optmulti("n", "", "nothing", "NOTHING")
+        .optopt("", "notpresent", "nothing to see here", "NOPE")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            assert!(m.free[0] == "prog");
+            assert!(m.free[1] == "free1");
+            assert_eq!(m.opt_str("s").unwrap(), "20");
+            assert!(m.free[2] == "free2");
+            assert!((m.opt_present("flag")));
+            assert_eq!(m.opt_str("long").unwrap(), "30");
+            assert!((m.opt_present("f")));
+            let pair = m.opt_strs("m");
+            assert!(pair[0] == "40");
+            assert!(pair[1] == "50");
+            let pair = m.opt_strs("n");
+            assert!(pair[0] == "-A B");
+            assert!(pair[1] == "-60 70");
+            assert!((!m.opt_present("notpresent")));
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_mixed_stop() {
+    let args = vec![
+        "-a".to_string(),
+        "b".to_string(),
+        "-c".to_string(),
+        "d".to_string(),
+    ];
+    match Options::new()
+        .parsing_style(ParsingStyle::StopAtFirstFree)
+        .optflag("a", "", "")
+        .optopt("c", "", "", "")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            println!("{}", m.opt_present("c"));
+            assert!(m.opt_present("a"));
+            assert!(!m.opt_present("c"));
+            assert_eq!(m.free.len(), 3);
+            assert_eq!(m.free[0], "b");
+            assert_eq!(m.free[1], "-c");
+            assert_eq!(m.free[2], "d");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_mixed_stop_hyphen() {
+    let args = vec![
+        "-a".to_string(),
+        "-".to_string(),
+        "-c".to_string(),
+        "d".to_string(),
+    ];
+    match Options::new()
+        .parsing_style(ParsingStyle::StopAtFirstFree)
+        .optflag("a", "", "")
+        .optopt("c", "", "", "")
+        .parse(&args)
+    {
+        Ok(ref m) => {
+            println!("{}", m.opt_present("c"));
+            assert!(m.opt_present("a"));
+            assert!(!m.opt_present("c"));
+            assert_eq!(m.free.len(), 3);
+            assert_eq!(m.free[0], "-");
+            assert_eq!(m.free[1], "-c");
+            assert_eq!(m.free[2], "d");
+        }
+        _ => panic!(),
+    }
+}
+
+#[test]
+fn test_multi() {
+    let mut opts = Options::new();
+    opts.optopt("e", "", "encrypt", "ENCRYPT");
+    opts.optopt("", "encrypt", "encrypt", "ENCRYPT");
+    opts.optopt("f", "", "flag", "FLAG");
+
+    let args_single = vec!["-e".to_string(), "foo".to_string()];
+    let matches_single = &match opts.parse(&args_single) {
+        Ok(m) => m,
+        _ => panic!(),
+    };
+    assert!(matches_single.opts_present(&["e".to_string()]));
+    assert!(matches_single.opts_present(&["encrypt".to_string(), "e".to_string()]));
+    assert!(matches_single.opts_present(&["e".to_string(), "encrypt".to_string()]));
+    assert!(!matches_single.opts_present(&["encrypt".to_string()]));
+    assert!(!matches_single.opts_present(&["thing".to_string()]));
+    assert!(!matches_single.opts_present(&[]));
+
+    assert_eq!(matches_single.opts_str(&["e".to_string()]).unwrap(), "foo");
+    assert_eq!(
+        matches_single
+            .opts_str(&["e".to_string(), "encrypt".to_string()])
+            .unwrap(),
+        "foo"
+    );
+    assert_eq!(
+        matches_single
+            .opts_str(&["encrypt".to_string(), "e".to_string()])
+            .unwrap(),
+        "foo"
+    );
+
+    let args_both = vec![
+        "-e".to_string(),
+        "foo".to_string(),
+        "--encrypt".to_string(),
+        "foo".to_string(),
+    ];
+    let matches_both = &match opts.parse(&args_both) {
+        Ok(m) => m,
+        _ => panic!(),
+    };
+    assert!(matches_both.opts_present(&["e".to_string()]));
+    assert!(matches_both.opts_present(&["encrypt".to_string()]));
+    assert!(matches_both.opts_present(&["encrypt".to_string(), "e".to_string()]));
+    assert!(matches_both.opts_present(&["e".to_string(), "encrypt".to_string()]));
+    assert!(!matches_both.opts_present(&["f".to_string()]));
+    assert!(!matches_both.opts_present(&["thing".to_string()]));
+    assert!(!matches_both.opts_present(&[]));
+
+    assert_eq!(matches_both.opts_str(&["e".to_string()]).unwrap(), "foo");
+    assert_eq!(
+        matches_both.opts_str(&["encrypt".to_string()]).unwrap(),
+        "foo"
+    );
+    assert_eq!(
+        matches_both
+            .opts_str(&["e".to_string(), "encrypt".to_string()])
+            .unwrap(),
+        "foo"
+    );
+    assert_eq!(
+        matches_both
+            .opts_str(&["encrypt".to_string(), "e".to_string()])
+            .unwrap(),
+        "foo"
+    );
+}
+
+#[test]
+fn test_nospace() {
+    let args = vec!["-Lfoo".to_string(), "-M.".to_string()];
+    let matches = &match Options::new()
+        .optmulti("L", "", "library directory", "LIB")
+        .optmulti("M", "", "something", "MMMM")
+        .parse(&args)
+    {
+        Ok(m) => m,
+        _ => panic!(),
+    };
+    assert!(matches.opts_present(&["L".to_string()]));
+    assert_eq!(matches.opts_str(&["L".to_string()]).unwrap(), "foo");
+    assert!(matches.opts_present(&["M".to_string()]));
+    assert_eq!(matches.opts_str(&["M".to_string()]).unwrap(), ".");
+}
+
+#[test]
+fn test_nospace_conflict() {
+    let args = vec!["-vvLverbose".to_string(), "-v".to_string()];
+    let matches = &match Options::new()
+        .optmulti("L", "", "library directory", "LIB")
+        .optflagmulti("v", "verbose", "Verbose")
+        .parse(&args)
+    {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert!(matches.opts_present(&["L".to_string()]));
+    assert_eq!(matches.opts_str(&["L".to_string()]).unwrap(), "verbose");
+    assert!(matches.opts_present(&["v".to_string()]));
+    assert_eq!(3, matches.opt_count("v"));
+}
+
+#[test]
+fn test_long_to_short() {
+    let mut short = Opt {
+        name: Name::Long("banana".to_string()),
+        hasarg: HasArg::Yes,
+        occur: Occur::Req,
+        aliases: Vec::new(),
+    };
+    short.aliases = vec![Opt {
+        name: Name::Short('b'),
+        hasarg: HasArg::Yes,
+        occur: Occur::Req,
+        aliases: Vec::new(),
+    }];
+    let mut opts = Options::new();
+    opts.reqopt("b", "banana", "some bananas", "VAL");
+    let verbose = &opts.grps[0];
+    assert!(verbose.long_to_short() == short);
+}
+
+#[test]
+fn test_aliases_long_and_short() {
+    let args = vec!["-a".to_string(), "--apple".to_string(), "-a".to_string()];
+
+    let matches = Options::new()
+        .optflagmulti("a", "apple", "Desc")
+        .parse(&args)
+        .unwrap();
+    assert_eq!(3, matches.opt_count("a"));
+    assert_eq!(3, matches.opt_count("apple"));
+}
+
+#[test]
+fn test_usage() {
+    let mut opts = Options::new();
+    opts.reqopt("b", "banana", "Desc", "VAL");
+    opts.optopt("a", "012345678901234567890123456789", "Desc", "VAL");
+    opts.optflag("k", "kiwi", "Desc");
+    opts.optflagopt("p", "", "Desc", "VAL");
+    opts.optmulti("l", "", "Desc", "VAL");
+    opts.optflag("", "starfruit", "Starfruit");
+
+    let expected = "Usage: fruits
+
+Options:
+    -b, --banana VAL    Desc
+    -a, --012345678901234567890123456789 VAL
+                        Desc
+    -k, --kiwi          Desc
+    -p [VAL]            Desc
+    -l VAL              Desc
+        --starfruit     Starfruit
+";
+
+    let generated_usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", generated_usage);
+    assert_eq!(generated_usage, expected);
+}
+
+#[test]
+fn test_usage_description_wrapping() {
+    // indentation should be 24 spaces
+    // lines wrap after 78: or rather descriptions wrap after 54
+
+    let mut opts = Options::new();
+    opts.optflag(
+        "k",
+        "kiwi",
+        "This is a long description which won't be wrapped..+..",
+    ); // 54
+    opts.optflag(
+        "a",
+        "apple",
+        "This is a long description which _will_ be wrapped..+..",
+    );
+    opts.optflag(
+        "b",
+        "banana",
+        "HereWeNeedOneSingleWordThatIsLongerThanTheWrappingLengthAndThisIsIt",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, --kiwi          This is a long description which won't be wrapped..+..
+    -a, --apple         This is a long description which _will_ be
+                        wrapped..+..
+    -b, --banana        HereWeNeedOneSingleWordThatIsLongerThanTheWrappingLengthAndThisIsIt
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_usage_description_multibyte_handling() {
+    let mut opts = Options::new();
+    opts.optflag(
+        "k",
+        "k\u{2013}w\u{2013}",
+        "The word kiwi is normally spelled with two i's",
+    );
+    opts.optflag(
+        "a",
+        "apple",
+        "This \u{201C}description\u{201D} has some characters that could \
+         confuse the line wrapping; an apple costs 0.51€ in some parts of Europe.",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, --k–w–          The word kiwi is normally spelled with two i's
+    -a, --apple         This “description” has some characters that could
+                        confuse the line wrapping; an apple costs 0.51€ in
+                        some parts of Europe.
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_usage_description_newline_handling() {
+    let mut opts = Options::new();
+    opts.optflag(
+        "k",
+        "k\u{2013}w\u{2013}",
+        "The word kiwi is normally spelled with two i's",
+    );
+    opts.optflag(
+        "a",
+        "apple",
+        "This description forces a new line.\n Here is a premature\n\
+         newline",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, --k–w–          The word kiwi is normally spelled with two i's
+    -a, --apple         This description forces a new line.
+                        Here is a premature
+                        newline
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_usage_multiwidth() {
+    let mut opts = Options::new();
+    opts.optflag("a", "apple", "apple description");
+    opts.optflag("b", "banana\u{00AB}", "banana description");
+    opts.optflag("c", "brûlée", "brûlée quite long description");
+    opts.optflag("k", "kiwi\u{20AC}", "kiwi description");
+    opts.optflag("o", "orange\u{2039}", "orange description");
+    opts.optflag(
+        "r",
+        "raspberry-but-making-this-option-way-too-long",
+        "raspberry description is also quite long indeed longer than \
+         every other piece of text we might encounter here and thus will \
+         be automatically broken up",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -a, --apple         apple description
+    -b, --banana«       banana description
+    -c, --brûlée        brûlée quite long description
+    -k, --kiwi€         kiwi description
+    -o, --orange‹       orange description
+    -r, --raspberry-but-making-this-option-way-too-long\u{0020}
+                        raspberry description is also quite long indeed longer
+                        than every other piece of text we might encounter here
+                        and thus will be automatically broken up
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_usage_short_only() {
+    let mut opts = Options::new();
+    opts.optopt("k", "", "Kiwi", "VAL");
+    opts.optflag("s", "", "Starfruit");
+    opts.optflagopt("a", "", "Apple", "TYPE");
+
+    let expected = "Usage: fruits
+
+Options:
+    -k VAL              Kiwi
+    -s                  Starfruit
+    -a [TYPE]           Apple
+";
+
+    let usage = opts.usage("Usage: fruits");
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_usage_long_only() {
+    let mut opts = Options::new();
+    opts.optopt("", "kiwi", "Kiwi", "VAL");
+    opts.optflag("", "starfruit", "Starfruit");
+    opts.optflagopt("", "apple", "Apple", "TYPE");
+
+    let expected = "Usage: fruits
+
+Options:
+    --kiwi VAL          Kiwi
+    --starfruit         Starfruit
+    --apple [TYPE]      Apple
+";
+
+    let usage = opts.usage("Usage: fruits");
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_short_usage() {
+    let mut opts = Options::new();
+    opts.reqopt("b", "banana", "Desc", "VAL");
+    opts.optopt("a", "012345678901234567890123456789", "Desc", "VAL");
+    opts.optflag("k", "kiwi", "Desc");
+    opts.optflagopt("p", "", "Desc", "VAL");
+    opts.optmulti("l", "", "Desc", "VAL");
+
+    let expected = "Usage: fruits -b VAL [-a VAL] [-k] [-p [VAL]] [-l VAL]..".to_string();
+    let generated_usage = opts.short_usage("fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", generated_usage);
+    assert_eq!(generated_usage, expected);
+}
+#[test]
+fn test_nonexistant_opt() {
+    let mut opts = Options::new();
+    opts.optflag("b", "bar", "Desc");
+    let args: Vec<String> = Vec::new();
+    let matches = opts.parse(&args).unwrap();
+    assert_eq!(matches.opt_defined("foo"), false);
+    assert_eq!(matches.opt_defined("bar"), true);
+}
+#[test]
+fn test_args_with_equals() {
+    let mut opts = Options::new();
+    opts.optopt("o", "one", "One", "INFO");
+    opts.optopt("t", "two", "Two", "INFO");
+
+    let args = vec![
+        "--one".to_string(),
+        "A=B".to_string(),
+        "--two=C=D".to_string(),
+    ];
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert_eq!(matches.opts_str(&["o".to_string()]).unwrap(), "A=B");
+    assert_eq!(matches.opts_str(&["t".to_string()]).unwrap(), "C=D");
+}
+
+#[test]
+fn test_long_only_usage() {
+    let mut opts = Options::new();
+    opts.long_only(true);
+    opts.optflag("k", "kiwi", "Description");
+    opts.optflag("a", "apple", "Description");
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, -kiwi           Description
+    -a, -apple          Description
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
+#[test]
+fn test_long_only_mode() {
+    let mut opts = Options::new();
+    opts.long_only(true);
+    opts.optopt("a", "apple", "Description", "X");
+    opts.optopt("b", "banana", "Description", "X");
+    opts.optopt("c", "currant", "Description", "X");
+    opts.optopt("", "durian", "Description", "X");
+    opts.optopt("e", "", "Description", "X");
+    opts.optopt("", "fruit", "Description", "X");
+
+    let args = vec![
+        "-a",
+        "A",
+        "-b=B",
+        "--c=C",
+        "-durian",
+        "D",
+        "--e",
+        "E",
+        "-fruit=any",
+    ];
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert_eq!(matches.opts_str(&["a".to_string()]).unwrap(), "A");
+    assert_eq!(matches.opts_str(&["b".to_string()]).unwrap(), "B");
+    assert_eq!(matches.opts_str(&["c".to_string()]).unwrap(), "C");
+    assert_eq!(matches.opts_str(&["durian".to_string()]).unwrap(), "D");
+    assert_eq!(matches.opts_str(&["e".to_string()]).unwrap(), "E");
+    assert_eq!(matches.opts_str(&["fruit".to_string()]).unwrap(), "any");
+}
+
+#[test]
+fn test_long_only_mode_no_short_parse() {
+    let mut opts = Options::new();
+    opts.long_only(true);
+    opts.optflag("h", "help", "Description");
+    opts.optflag("i", "ignore", "Description");
+    opts.optflag("", "hi", "Description");
+
+    let args = vec!["-hi"];
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert!(matches.opt_present("hi"));
+    assert!(!matches.opt_present("h"));
+    assert!(!matches.opt_present("i"));
+}
+
+#[test]
+fn test_normal_mode_no_long_parse() {
+    // Like test_long_only_mode_no_short_parse, but we make sure
+    // that long_only can be disabled, and the right thing
+    // happens.
+    let mut opts = Options::new();
+    opts.long_only(true);
+    opts.optflag("h", "help", "Description");
+    opts.optflag("i", "ignore", "Description");
+    opts.optflag("", "hi", "Description");
+    opts.long_only(false);
+
+    let args = vec!["-hi"];
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert!(!matches.opt_present("hi"));
+    assert!(matches.opt_present("h"));
+    assert!(matches.opt_present("i"));
+}
+
+#[test]
+#[should_panic]
+fn test_long_name_too_short() {
+    let mut opts = Options::new();
+    opts.optflag("", "a", "Oops, long option too short");
+}
+
+#[test]
+#[should_panic]
+fn test_undefined_opt_present() {
+    let mut opts = Options::new();
+    opts.optflag("h", "help", "Description");
+    let args = vec!["-h"];
+    match opts.parse(args) {
+        Ok(matches) => assert!(!matches.opt_present("undefined")),
+        Err(e) => panic!("{}", e),
+    }
+}
+
+#[test]
+fn test_opt_default() {
+    let mut opts = Options::new();
+    opts.optflag("h", "help", "Description");
+    opts.optflag("i", "ignore", "Description");
+    opts.optflag("r", "run", "Description");
+    opts.long_only(false);
+
+    let args: Vec<String> = ["-i", "-r", "10"].iter().map(|x| x.to_string()).collect();
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    assert_eq!(matches.opt_default("help", ""), None);
+    assert_eq!(matches.opt_default("i", "def"), Some("def".to_string()));
+}
+
+#[test]
+fn test_opt_get() {
+    let mut opts = Options::new();
+    opts.optflag("h", "help", "Description");
+    opts.optflagopt("i", "ignore", "Description", "true | false");
+    opts.optflagopt("r", "run", "Description", "0 .. 10");
+    opts.optflagopt("p", "percent", "Description", "0.0 .. 10.0");
+    opts.long_only(false);
+
+    let args: Vec<String> = ["-i", "true", "-p", "1.1"]
+        .iter()
+        .map(|x| x.to_string())
+        .collect();
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    let h_arg = matches.opt_get::<i32>("help");
+    assert_eq!(h_arg, Ok(None));
+    let i_arg = matches.opt_get("i");
+    assert_eq!(i_arg, Ok(Some(true)));
+    let p_arg = matches.opt_get("p");
+    assert_eq!(p_arg, Ok(Some(1.1)));
+}
+
+#[test]
+fn test_opt_get_default() {
+    let mut opts = Options::new();
+    opts.optflag("h", "help", "Description");
+    opts.optflagopt("i", "ignore", "Description", "true | false");
+    opts.optflagopt("r", "run", "Description", "0 .. 10");
+    opts.optflagopt("p", "percent", "Description", "0.0 .. 10.0");
+    opts.long_only(false);
+
+    let args: Vec<String> = ["-i", "true", "-p", "1.1"]
+        .iter()
+        .map(|x| x.to_string())
+        .collect();
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+    let h_arg = matches.opt_get_default("help", 10);
+    assert_eq!(h_arg, Ok(10));
+    let i_arg = matches.opt_get_default("i", false);
+    assert_eq!(i_arg, Ok(true));
+    let p_arg = matches.opt_get_default("p", 10.2);
+    assert_eq!(p_arg, Ok(1.1));
+}
+
+#[test]
+fn test_opt_positions() {
+    let mut opts = Options::new();
+    opts.optflagmulti("a", "act", "Description");
+    opts.optflagmulti("e", "enact", "Description");
+    opts.optflagmulti("r", "react", "Description");
+
+    let args: Vec<String> = ["-a", "-a", "-r", "-a", "-r", "-r"]
+        .iter()
+        .map(|x| x.to_string())
+        .collect();
+
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+
+    let a_pos = matches.opt_positions("a");
+    assert_eq!(a_pos, vec![0, 1, 3]);
+    let e_pos = matches.opt_positions("e");
+    assert_eq!(e_pos, vec![]);
+    let r_pos = matches.opt_positions("r");
+    assert_eq!(r_pos, vec![2, 4, 5]);
+}
+
+#[test]
+fn test_opt_strs_pos() {
+    let mut opts = Options::new();
+    opts.optmulti("a", "act", "Description", "NUM");
+    opts.optmulti("e", "enact", "Description", "NUM");
+    opts.optmulti("r", "react", "Description", "NUM");
+
+    let args: Vec<String> = ["-a1", "-a2", "-r3", "-a4", "-r5", "-r6"]
+        .iter()
+        .map(|x| x.to_string())
+        .collect();
+
+    let matches = &match opts.parse(&args) {
+        Ok(m) => m,
+        Err(e) => panic!("{}", e),
+    };
+
+    let a_pos = matches.opt_strs_pos("a");
+    assert_eq!(
+        a_pos,
+        vec![
+            (0, "1".to_string()),
+            (1, "2".to_string()),
+            (3, "4".to_string())
+        ]
+    );
+    let e_pos = matches.opt_strs_pos("e");
+    assert_eq!(e_pos, vec![]);
+    let r_pos = matches.opt_strs_pos("r");
+    assert_eq!(
+        r_pos,
+        vec![
+            (2, "3".to_string()),
+            (4, "5".to_string()),
+            (5, "6".to_string())
+        ]
+    );
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/tests/smoke.rs b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/tests/smoke.rs
new file mode 100644
index 000000000000..a46f9c0167ab
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/tests/smoke.rs
@@ -0,0 +1,8 @@
+extern crate getopts;
+
+use std::env;
+
+#[test]
+fn main() {
+    getopts::Options::new().parse(env::args()).unwrap();
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo_vcs_info.json
new file mode 100644
index 000000000000..d4af33b2aad2
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "9b679189639fec8d449cd2f1759fad5dc0ef38db"
+  },
+  "path_in_vcs": "phf_macros"
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/CHANGELOG.md b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/CHANGELOG.md
new file mode 100644
index 000000000000..a71d84180fde
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/CHANGELOG.md
@@ -0,0 +1,361 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## 0.11.3 (2025-01-07)
+
+### Other
+
+ - <csr-id-9ed628fe2ca954fdc49a93331188a99b58c9363a/> include LICENSE and changelog files in published crates
+   The restrictive "include" directive is only present in the phf_macros
+   crate but in none of the others. This commit brings phf_macros crate
+   in line with other crates in this workspace.
+
+### Bug Fixes
+
+ - <csr-id-b54c740086a96da85056b0df28174122bd73d5b0/> Add isize/usize as valid key types
+   These types already implement PhfHash as of #262, but were not supported
+   as valid key expressions in `phf_map!` and co.
+
+### Chore
+
+ - <csr-id-a96a4e29d63fb1ab3cc10e050571e733f5d2d0d1/> bump Cargo.toml version of phf and phf_macros
+
+### Commit Statistics
+
+<csr-read-only-do-not-edit/>
+
+ - 10 commits contributed to the release.
+ - 562 days passed between releases.
+ - 3 commits were understood as [conventional](https://www.conventionalcommits.org).
+ - 0 issues like '(#ID)' were seen in commit messages
+
+### Commit Details
+
+<csr-read-only-do-not-edit/>
+
+<details><summary>view details</summary>
+
+ * **Uncategorized**
+    - Adjusting changelogs prior to release of phf_shared v0.11.3, phf_generator v0.11.3, phf_macros v0.11.3, phf v0.11.3, phf_codegen v0.11.3 ([`a95dade`](https://github.com/rust-phf/rust-phf/commit/a95dade6f69866b7871f85dd3fd42984df2f3d28))
+    - Merge pull request #322 from JohnTitor/release-0.11.3 ([`dc64dd6`](https://github.com/rust-phf/rust-phf/commit/dc64dd6bace986a8858590455e08659d9ea4ae4b))
+    - Reset version num ([`13581f8`](https://github.com/rust-phf/rust-phf/commit/13581f8e9eefe8b8b7cb1b1ad04f2d68d97b0ffd))
+    - Merge pull request #315 from LunarLambda/master ([`695a0df`](https://github.com/rust-phf/rust-phf/commit/695a0df769f3c75150a67ed9bb316579b875289d))
+    - Bump Cargo.toml version of phf and phf_macros ([`a96a4e2`](https://github.com/rust-phf/rust-phf/commit/a96a4e29d63fb1ab3cc10e050571e733f5d2d0d1))
+    - Add isize/usize as valid key types ([`b54c740`](https://github.com/rust-phf/rust-phf/commit/b54c740086a96da85056b0df28174122bd73d5b0))
+    - Merge pull request #300 from JohnTitor/msrv-1.61 ([`323366d`](https://github.com/rust-phf/rust-phf/commit/323366d03966ddad2eaa3432df79c9da8339e319))
+    - Bump MSRV to 1.61 ([`1795f7b`](https://github.com/rust-phf/rust-phf/commit/1795f7b66b16af0191f221dc957bc8a090c891ad))
+    - Merge pull request #293 from decathorpe/master ([`e03f456`](https://github.com/rust-phf/rust-phf/commit/e03f4562957afd89d8d95a19d563eda9f0db7e8c))
+    - Include LICENSE and changelog files in published crates ([`9ed628f`](https://github.com/rust-phf/rust-phf/commit/9ed628fe2ca954fdc49a93331188a99b58c9363a))
+</details>
+
+## 0.11.2 (2023-06-24)
+
+### Commit Statistics
+
+<csr-read-only-do-not-edit/>
+
+ - 10 commits contributed to the release.
+ - 319 days passed between releases.
+ - 0 commits were understood as [conventional](https://www.conventionalcommits.org).
+ - 0 issues like '(#ID)' were seen in commit messages
+
+### Commit Details
+
+<csr-read-only-do-not-edit/>
+
+<details><summary>view details</summary>
+
+ * **Uncategorized**
+    - Release phf_shared v0.11.2, phf_generator v0.11.2, phf_macros v0.11.2, phf v0.11.2, phf_codegen v0.11.2 ([`c9c35fd`](https://github.com/rust-phf/rust-phf/commit/c9c35fd8ba3f1bc228388b0cef6e3814a02a72c0))
+    - Update changelogs ([`a1e5072`](https://github.com/rust-phf/rust-phf/commit/a1e5072b8e84b108f06389a1d41ac868426a03f7))
+    - Merge pull request #280 from jf2048/deref-bytestring ([`3776342`](https://github.com/rust-phf/rust-phf/commit/377634245c8c6f0569a2ed7b75d08366b54c8810))
+    - Merge pull request #284 from nickelc/deps/syn2 ([`5ec8936`](https://github.com/rust-phf/rust-phf/commit/5ec8936369ca9eb6392a4aeb878d9bfef88d0d17))
+    - Update `syn` to 2.0 ([`8e3e3e5`](https://github.com/rust-phf/rust-phf/commit/8e3e3e554433a2bcb6bf84805b1d03a49780d8c3))
+    - Allow using dereferenced bytestring literal keys in phf_map! ([`8c0d057`](https://github.com/rust-phf/rust-phf/commit/8c0d0572da8c0b5e188e7fda4ab8bd4bcb97f720))
+    - Merge pull request #274 from ankane/license-files ([`21baa73`](https://github.com/rust-phf/rust-phf/commit/21baa73941a0694ec48f437c0c0a6abfcc2f32d2))
+    - Include license files in crates ([`1229b2f`](https://github.com/rust-phf/rust-phf/commit/1229b2faa6b97542ab4850a1723b1723dea92814))
+    - Merge pull request #271 from DavidS/bump-dep ([`ea8df2c`](https://github.com/rust-phf/rust-phf/commit/ea8df2caad5b20f927be1f0174dfa4e68e8a95f6))
+    - Fix missed dependency bump in phf_macros ([`b7fd8f1`](https://github.com/rust-phf/rust-phf/commit/b7fd8f183f266cf7f0bf0ca8e89b03453f3f35b7))
+</details>
+
+## 0.11.1 (2022-08-08)
+
+<csr-id-d40d663ca96f668bcd6f86cc691085629111c0b5/>
+<csr-id-8225c4b90d6ee71483304e71342c269fca86a044/>
+
+### Chore
+
+ - <csr-id-d40d663ca96f668bcd6f86cc691085629111c0b5/> upgrade syn/proc-macro
+
+### Bug Fixes
+
+ - <csr-id-caf1ce71aed110fb44206ce2291154572ebfe9b7/> remove now-unnecessary `proc-macro-hack` crate usage
+   Resolves <https://github.com/rust-phf/rust-phf/issues/255>.
+   
+   This resolves an issue with Windows Defender identifying `proc-macro-hack` as threats. It also sheds
+   a depedency that is no longer necessary, now that the MSRV of this crate is 1.46 and
+   `proc-macro-hack` is only useful for providing support for Rust versions 1.31 through 1.45. Per
+   [upstream](https://github.com/dtolnay/proc-macro-hack):
+   
+   > **Note:** _As of Rust 1.45 this crate is superseded by native support for #\[proc\_macro\] in
+   > expression position. Only consider using this crate if you care about supporting compilers between
+   > 1.31 and 1.45._
+
+### Other
+
+ - <csr-id-8225c4b90d6ee71483304e71342c269fca86a044/> Update code for changes in Rust
+   LitBinary is now LitByteStr
+
+### Commit Statistics
+
+<csr-read-only-do-not-edit/>
+
+ - 232 commits contributed to the release.
+ - 3 commits were understood as [conventional](https://www.conventionalcommits.org).
+ - 0 issues like '(#ID)' were seen in commit messages
+
+### Commit Details
+
+<csr-read-only-do-not-edit/>
+
+<details><summary>view details</summary>
+
+ * **Uncategorized**
+    - Release phf_shared v0.11.1, phf_generator v0.11.1, phf_macros v0.11.1, phf v0.11.1, phf_codegen v0.11.1 ([`3897b21`](https://github.com/rust-phf/rust-phf/commit/3897b21c6d38e5adcaf9110b4bb33c19f6b41977))
+    - Merge pull request #264 from rust-phf/tweak-changelog ([`97f997d`](https://github.com/rust-phf/rust-phf/commit/97f997d2be827ca636a29046c78e2c09c5c62650))
+    - Replace handmade changelog with generated one by `cargo-smart-release` ([`cb84cf6`](https://github.com/rust-phf/rust-phf/commit/cb84cf6636ab52823c53e70d6abeac8f648a3482))
+    - Merge pull request #260 from JohnTitor/fix-repo-link ([`1407ebe`](https://github.com/rust-phf/rust-phf/commit/1407ebe536b39611db92d765ddec4de0e6c8a16e))
+    - Add category to crates ([`32a72c3`](https://github.com/rust-phf/rust-phf/commit/32a72c3859997fd6b590e9ec092ae789d2acdf55))
+    - Update repository links on Cargo.toml ([`1af3b0f`](https://github.com/rust-phf/rust-phf/commit/1af3b0fe1f8fdcae7ccc1bc8d51de309fb16a6bf))
+    - Merge pull request #258 from JohnTitor/release-0.11.0 ([`c0b9ef9`](https://github.com/rust-phf/rust-phf/commit/c0b9ef98e798f807f94544aeb0fff429ef280efc))
+    - Release 0.11.0 ([`d2efdc0`](https://github.com/rust-phf/rust-phf/commit/d2efdc08a7eb1d0d6c414b7b2ac41ce1fe1f9a43))
+    - Merge pull request #257 from JohnTitor/edition-2021 ([`36ec885`](https://github.com/rust-phf/rust-phf/commit/36ec8854a9da4f295618e98d94aaf7150df2173e))
+    - Make crates edition 2021 ([`b9d25da`](https://github.com/rust-phf/rust-phf/commit/b9d25da58b912d9927fbc41901631cd77836462b))
+    - Merge pull request #256 from NZXTCorp/remove-proc-macro-hack ([`a85f070`](https://github.com/rust-phf/rust-phf/commit/a85f070d641317a04b81da053cc4040619652e69))
+    - Remove now-unnecessary `proc-macro-hack` crate usage ([`caf1ce7`](https://github.com/rust-phf/rust-phf/commit/caf1ce71aed110fb44206ce2291154572ebfe9b7))
+    - Merge pull request #251 from JohnTitor/weak-deps ([`2e1167c`](https://github.com/rust-phf/rust-phf/commit/2e1167c2046cd20aed1a906b4e23b40303cf0c00))
+    - Make "unicase + macros" features work ([`11bb242`](https://github.com/rust-phf/rust-phf/commit/11bb2426f0237b1ecea8c8038630b1231ede4871))
+    - Merge pull request #241 from JohnTitor/extract-macro-tests ([`7b0a313`](https://github.com/rust-phf/rust-phf/commit/7b0a3130a55176d2570300f92cb7ddca6c23da83))
+    - Extract `phf_macros` tests as a separated crate ([`8cf694d`](https://github.com/rust-phf/rust-phf/commit/8cf694d76e0991b4e24ecdc5d2a88bb74713d9cd))
+    - Merge pull request #240 from JohnTitor/docs-update ([`da98b9e`](https://github.com/rust-phf/rust-phf/commit/da98b9e80fdb22cd6d48a4a42489840afe603756))
+    - Remove some stuff which is now unnecessary ([`6941e82`](https://github.com/rust-phf/rust-phf/commit/6941e825d09a98c1ea29a08ecd5fd605611584a4))
+    - Refine doc comments ([`d8cfc43`](https://github.com/rust-phf/rust-phf/commit/d8cfc436059a1c2c3ede1afb0f9ec2333c046fc6))
+    - Merge pull request #234 from JohnTitor/fix-ci ([`eba4cc2`](https://github.com/rust-phf/rust-phf/commit/eba4cc28d92c1db95cc430985a0fbc9ca63d1307))
+    - Fix CI failure ([`d9b5ff2`](https://github.com/rust-phf/rust-phf/commit/d9b5ff23367d2bbcc385ff8243c7d972f45d459c))
+    - Fix `phf` dev dep version ([`3cc6f05`](https://github.com/rust-phf/rust-phf/commit/3cc6f05cb07933af4cf886645d1170bdcb306b6b))
+    - Merge pull request #230 from JohnTitor/release-0.10 ([`3ea14b2`](https://github.com/rust-phf/rust-phf/commit/3ea14b2166553ad6e7b9afe7244144f5d661b6c6))
+    - Prepare for release 0.10.0 ([`588ac25`](https://github.com/rust-phf/rust-phf/commit/588ac25dd5c0afccea084e6f94867328a6a30454))
+    - Fix publish failure ([`fbb18f9`](https://github.com/rust-phf/rust-phf/commit/fbb18f925018fa621ce8a8d334f6746ae0f1d072))
+    - Merge pull request #228 from JohnTitor/release-0.9.1 ([`d527f9d`](https://github.com/rust-phf/rust-phf/commit/d527f9d016adafe7d2930e37710291030b432838))
+    - Prepare for v0.9.1 ([`9b71978`](https://github.com/rust-phf/rust-phf/commit/9b719789149ef195ef5eba093b7e73255fbef8dc))
+    - Merge pull request #224 from bhgomes/const-fns ([`65deaf7`](https://github.com/rust-phf/rust-phf/commit/65deaf745b5175b6b8e645b6c66e53fc55bb3a85))
+    - Remove Slice type and fix some docs ([`99d3533`](https://github.com/rust-phf/rust-phf/commit/99d353390f8124a283da9202fd4d163e68bc1949))
+    - Merge pull request #223 from JohnTitor/minor-cleanup ([`c746106`](https://github.com/rust-phf/rust-phf/commit/c746106ad05917ad62f244504727b07e07c3e075))
+    - Minor cleanups ([`8868d08`](https://github.com/rust-phf/rust-phf/commit/8868d088e2fed36fcd7741e9a1c5bf68bef4f46e))
+    - Merge pull request #222 from JohnTitor/precisify-msrv ([`50f8a0d`](https://github.com/rust-phf/rust-phf/commit/50f8a0d3d3f4cc7e15146e29e0559ba057a25a4d))
+    - Bless tests ([`dab668c`](https://github.com/rust-phf/rust-phf/commit/dab668ccc8b638548cd78678de8427ed5e765b21))
+    - Merge pull request #220 from JohnTitor/fix-release-process ([`29f9100`](https://github.com/rust-phf/rust-phf/commit/29f910079b75623420a19f3bd91a341821e02118))
+    - Fix the release failure ([`647f331`](https://github.com/rust-phf/rust-phf/commit/647f331d43dcf2b61625cccffbd31f95ad076d05))
+    - Downgrade `phf` dev-dep version for now ([`7dd8a1b`](https://github.com/rust-phf/rust-phf/commit/7dd8a1b410fea96820bfe489f53f1c6fd9d64ba5))
+    - Merge pull request #219 from JohnTitor/release-0.9.0 ([`307969f`](https://github.com/rust-phf/rust-phf/commit/307969ff3bb8cae320e648890a9525920035944b))
+    - Prepare 0.9.0 release ([`2ca46c4`](https://github.com/rust-phf/rust-phf/commit/2ca46c4f9c9083c128fcc6add33dc5986638940f))
+    - Cleanup cargo metadata ([`a9e4b0a`](https://github.com/rust-phf/rust-phf/commit/a9e4b0a1e84825004fa66e938b870f83d3147d0d))
+    - Merge pull request #218 from JohnTitor/cleanup ([`76f9072`](https://github.com/rust-phf/rust-phf/commit/76f907239af9b0cca7dac4e6d702cedc72f6f371))
+    - Fix test ([`ffa7e41`](https://github.com/rust-phf/rust-phf/commit/ffa7e41a767dd6021a7f42f012dab0befe6d0932))
+    - Run rustfmt check on CI ([`1adfb30`](https://github.com/rust-phf/rust-phf/commit/1adfb305704cbced7c63e58b99bd53847298dbe6))
+    - Run rustfmt ([`dd86c6c`](https://github.com/rust-phf/rust-phf/commit/dd86c6c103f25021b52144085b8fab0a94582bef))
+    - Merge pull request #217 from JohnTitor/rename-feature ([`ff77659`](https://github.com/rust-phf/rust-phf/commit/ff77659a001c08f1f069a17cc5d2ff6fdd51569c))
+    - Rename `unicase_support` to `unicase` ([`b47174b`](https://github.com/rust-phf/rust-phf/commit/b47174bb9ebbd68e41316e1aa39c6541a45356a6))
+    - Merge pull request #215 from rust-phf/gha ([`12121ec`](https://github.com/rust-phf/rust-phf/commit/12121ec6d16d79d73cf9a2a7cdae1681798351b4))
+    - Run UI tests only on stable ([`7522b16`](https://github.com/rust-phf/rust-phf/commit/7522b160e76e981e430f6586dbfa8747c85f2f76))
+    - Merge pull request #205 from skyfloogle/ordered-stuff ([`9ae1678`](https://github.com/rust-phf/rust-phf/commit/9ae1678f2507d6d26a1b780385a2e17bdfbb0b5c))
+    - Add back ordered_map, ordered_set ([`0ab0108`](https://github.com/rust-phf/rust-phf/commit/0ab01081e4bd8f40bc18ab554c95f217220228d5))
+    - Merge pull request #209 from JohnTitor/unicase_support ([`ec43f5c`](https://github.com/rust-phf/rust-phf/commit/ec43f5c912e48d7f56a4126fca8247733baee18f))
+    - Improve implementation for unicase support ([`6957e47`](https://github.com/rust-phf/rust-phf/commit/6957e470b6fcd3b389440bf3d2ddcb12e1d38911))
+    - Restore unicase_support for phf_macros ([`77e6cce`](https://github.com/rust-phf/rust-phf/commit/77e6cce1931fe8b43e434061a369f3620b3e97e0))
+    - Merge pull request #208 from JohnTitor/simplify-workspace ([`a47ac36`](https://github.com/rust-phf/rust-phf/commit/a47ac36b16dd8798659be3e24f74051cd1ed760d))
+    - Use `[patch.crates-io]` section instead of path key ([`f47515b`](https://github.com/rust-phf/rust-phf/commit/f47515bce5c433214dbecee262a7a6f14e6a74d4))
+    - Merge pull request #206 from Kazurin-775/master ([`7ebc9e7`](https://github.com/rust-phf/rust-phf/commit/7ebc9e7986ca9ae86c6e871b4fd495a401d6b5ca))
+    - Fix phf_macros on no_std ([`d7af3dc`](https://github.com/rust-phf/rust-phf/commit/d7af3dc96a67070e2f9000158d074825f0a9d592))
+    - Merge pull request #207 from JohnTitor/fix-ci ([`5b42ba6`](https://github.com/rust-phf/rust-phf/commit/5b42ba673ac03299799a69b317dfff90a994b240))
+    - Update stderrs ([`0f1407e`](https://github.com/rust-phf/rust-phf/commit/0f1407ec8aa6df74e7ed95dd073685295958d5d5))
+    - Merge pull request #201 from benesch/rand-08-redux ([`73a6799`](https://github.com/rust-phf/rust-phf/commit/73a6799f048228039af32c8e21246a63d977c9e3))
+    - Update expected test case output for latest nightly ([`e387f69`](https://github.com/rust-phf/rust-phf/commit/e387f69540138026ab679537322c94500876fe8d))
+    - Merge pull request #180 from abonander/master ([`81c7cc5`](https://github.com/rust-phf/rust-phf/commit/81c7cc5b48649108428671d3b8ad151f6fbdb359))
+    - Release v0.8.0 ([`4060288`](https://github.com/rust-phf/rust-phf/commit/4060288dc2c1ebe3b0630e4016ed51935bb0c863))
+    - Merge pull request #181 from mati865/criterion ([`696eee1`](https://github.com/rust-phf/rust-phf/commit/696eee1f38213fe4a404ddfb9ef10d8e61ef0700))
+    - Avoid missing main error in tests ([`1992222`](https://github.com/rust-phf/rust-phf/commit/19922229dfe8c25076ab13344a0b876fe2c3bda3))
+    - Merge pull request #179 from FauxFaux/bumps ([`5f86fa4`](https://github.com/rust-phf/rust-phf/commit/5f86fa46ebf28eb6ef83d70d58b1212795639ba3))
+    - Upgrade syn/proc-macro ([`d40d663`](https://github.com/rust-phf/rust-phf/commit/d40d663ca96f668bcd6f86cc691085629111c0b5))
+    - Merge pull request #171 from abonander/170-removals ([`0d00821`](https://github.com/rust-phf/rust-phf/commit/0d0082178568036736bb6d51cb91f95ca5a616c3))
+    - Remove ordered_map, ordered_set, phf_builder ([`8ae2bb8`](https://github.com/rust-phf/rust-phf/commit/8ae2bb886841a69a4fc482f439e2374f2373ab15))
+    - Merge pull request #166 from abonander/158-trybuild ([`50c6c75`](https://github.com/rust-phf/rust-phf/commit/50c6c75d406b529601f0377afba93e562bbff2aa))
+    - Port compile-fail tests to trybuild ([`4a4256c`](https://github.com/rust-phf/rust-phf/commit/4a4256cf1963a349c8d63f4f93c7c562e8963d59))
+    - Merge pull request #161 from abonander/display-builders ([`171f7ed`](https://github.com/rust-phf/rust-phf/commit/171f7edccb71766e9381600108a0d996513ec7ea))
+    - Create `Display` adapters for `phf_codegen` builders ([`93aa7ae`](https://github.com/rust-phf/rust-phf/commit/93aa7ae1de87345ea19f38e747283bc712384650))
+    - Merge pull request #164 from abonander/perf-improvements ([`70129c6`](https://github.com/rust-phf/rust-phf/commit/70129c6fbcdf428ce9f1014eea935301ac70e410))
+    - Ignore compiletest ([`f1362b2`](https://github.com/rust-phf/rust-phf/commit/f1362b25674538ed02d41fcc9f7cc1c8ba6ec57c))
+    - Merge pull request #160 from abonander/readme-edits ([`6e1f6ac`](https://github.com/rust-phf/rust-phf/commit/6e1f6ac9b1f917089a4501ccb32f4f477799e39c))
+    - Proc_macro_hygiene is not needed with proc-macro-hack ([`ab473a4`](https://github.com/rust-phf/rust-phf/commit/ab473a4c7fcc1a8e8a99594c261fe00b4ad96865))
+    - Merge pull request #149 from danielhenrymantilla/proc-macro-hack ([`ae649cd`](https://github.com/rust-phf/rust-phf/commit/ae649cd67d9ce1452092ee739971d8ee232505ee))
+    - Made macros work in stable ([`4fc0d1a`](https://github.com/rust-phf/rust-phf/commit/4fc0d1a8c3bcc3950082b614d8bfa4a0f63d6962))
+    - Merge branch 'master' into patch-1 ([`cd0d7ce`](https://github.com/rust-phf/rust-phf/commit/cd0d7ce1194252dcaca3153988ba2a4effa66b4f))
+    - Merge pull request #155 from abonander/128-bit-ints ([`6749552`](https://github.com/rust-phf/rust-phf/commit/674955292a7028752f2eb25e34c27e881f6b11a1))
+    - Implement support for 128-bit ints and fix high magnitude vals ([`5be5919`](https://github.com/rust-phf/rust-phf/commit/5be59199389c0703fff62f640eb1a0d19243fc48))
+    - Merge pull request #146 from Benjamin-L/master ([`d41f27d`](https://github.com/rust-phf/rust-phf/commit/d41f27d3e2bcbb4a2868a62b0e022b4bdb267d8b))
+    - Fixed typo in benchmark ([`f46b2e1`](https://github.com/rust-phf/rust-phf/commit/f46b2e19622de2f845ea5eb8e8d4f54ece364242))
+    - Fix tests ([`ae4ef3e`](https://github.com/rust-phf/rust-phf/commit/ae4ef3ea68d6baca0916b5ef2a15245ad78674ae))
+    - Release v0.7.24 ([`1287414`](https://github.com/rust-phf/rust-phf/commit/1287414b1302d2d717c5f4be81accf4c12ccad48))
+    - Reexport macros through phf crate ([`588fd1a`](https://github.com/rust-phf/rust-phf/commit/588fd1a785492afa5ad76db0556097e32e24387d))
+    - Convert phf_macros to new-style proc-macros ([`5ae4131`](https://github.com/rust-phf/rust-phf/commit/5ae413129c391223782bc2944ec0ffbded103791))
+    - Release v0.7.23 ([`a050b6f`](https://github.com/rust-phf/rust-phf/commit/a050b6f2a6b825bf0824339266ab9545340420d4))
+    - Update to nightly-2018-08-23 ([`e03f536`](https://github.com/rust-phf/rust-phf/commit/e03f536f32a8a2a31d07e43b19e05c7d4fd1cb82))
+    - Release 0.7.22 ([`ab88405`](https://github.com/rust-phf/rust-phf/commit/ab884054fa17eef915db2bdb5259c7aa71fbfea6))
+    - Fix build ([`2071d25`](https://github.com/rust-phf/rust-phf/commit/2071d2515ff37590c45ee2e88cead583cdb81089))
+    - Update to latest nightly ([`fcf758f`](https://github.com/rust-phf/rust-phf/commit/fcf758faa21c6c2c93dbab9fe6ac82a36bab0dd9))
+    - Upgrade rand ([`e7b5a35`](https://github.com/rust-phf/rust-phf/commit/e7b5a35d14f6927a748f3c55a1c87b5b751ececd))
+    - Release v0.7.21 ([`6c7e2d9`](https://github.com/rust-phf/rust-phf/commit/6c7e2d9ce17ff1b87507925bdbe87e6e682ed3e4))
+    - Merge pull request #101 from SimonSapin/rustup ([`8889199`](https://github.com/rust-phf/rust-phf/commit/888919958cd0b8bb1ca81b3e4d59fdb6716d30f1))
+    - Upgrade to rustc 1.16.0-nightly (c07a6ae77 2017-01-17) ([`dc756bf`](https://github.com/rust-phf/rust-phf/commit/dc756bfb1400715eeedd0dfaa394296274f59be4))
+    - Don't ICE on bad syntax ([`e87e95f`](https://github.com/rust-phf/rust-phf/commit/e87e95fb96cfad1cc6699b828fb8994d2429f424))
+    - Link to docs.rs ([`61142c5`](https://github.com/rust-phf/rust-phf/commit/61142c5aa168cff1bf53a6961ddc12012b49e1bb))
+    - Cleanup ([`9278c47`](https://github.com/rust-phf/rust-phf/commit/9278c470b33571de286314cae555c4de9dd7d177))
+    - Fix tests ([`5947cd1`](https://github.com/rust-phf/rust-phf/commit/5947cd14b9aac452f4f8feb25b57fd11240970ee))
+    - Remove time dependency ([`98f56e5`](https://github.com/rust-phf/rust-phf/commit/98f56e53c212795e048c7baa0f488e1b294e9c37))
+    - Dependency cleanup ([`f106aa6`](https://github.com/rust-phf/rust-phf/commit/f106aa66d85abfba3d627d12fd46a9b080c83e95))
+    - Release v0.7.20 ([`f631f50`](https://github.com/rust-phf/rust-phf/commit/f631f50abfaf6ea3d6fc8caaada47975b6df3a62))
+    - Merge pull request #96 from nox/rustup ([`2f509ca`](https://github.com/rust-phf/rust-phf/commit/2f509ca1a5e7910c3bc7aec773418098bc27d3ea))
+    - Update to Rust 1.15.0-nightly (7b3eeea22 2016-11-21) ([`39cc485`](https://github.com/rust-phf/rust-phf/commit/39cc485f777daaf2076f1da7337cc5ad7e9f00ad))
+    - Merge branch 'release' ([`ea7e256`](https://github.com/rust-phf/rust-phf/commit/ea7e2562706663632a0af65ae9fa94e5cf78c4ea))
+    - Merge branch 'release-v0.7.19' into release ([`81a4806`](https://github.com/rust-phf/rust-phf/commit/81a4806b05f14fb49aa972de27a42926a542ec44))
+    - Release v0.7.19 ([`0a98dd1`](https://github.com/rust-phf/rust-phf/commit/0a98dd1865d12a3fa4cc27bdb38fa1e7374940d9))
+    - Merge pull request #95 from nox/rustup ([`969bcd5`](https://github.com/rust-phf/rust-phf/commit/969bcd57629b97f06f3cf05453e36cd584cd85f7))
+    - Update phf_macros to Rust 1.14.0-nightly (7c69b0d5a 2016-11-01) ([`b7d2d4d`](https://github.com/rust-phf/rust-phf/commit/b7d2d4d36cb43a8fa159135250bd2265cb30f523))
+    - Merge branch 'release' ([`ecab54b`](https://github.com/rust-phf/rust-phf/commit/ecab54b8a028c88938f220dbb0a684e017bab62f))
+    - Merge branch 'release-v0.7.18' into release ([`dfa970b`](https://github.com/rust-phf/rust-phf/commit/dfa970b229cc32cfb2da1692aa94ad8a266e704a))
+    - Release v0.7.18 ([`3f71765`](https://github.com/rust-phf/rust-phf/commit/3f717650f4331f5dbb9d7a3f878228fcf1138729))
+    - Merge pull request #94 from Bobo1239/master ([`81f2a5d`](https://github.com/rust-phf/rust-phf/commit/81f2a5d7bc9897711a064b343b8a8b6216e252b7))
+    - Fix for latest nightly ([`35e991b`](https://github.com/rust-phf/rust-phf/commit/35e991b11efca3bd065a28f661ab76f423a83601))
+    - Merge branch 'release' ([`5f08563`](https://github.com/rust-phf/rust-phf/commit/5f0856327731107d9fada1b0318f6f15f32957c2))
+    - Merge branch 'release-v0.7.17' into release ([`e073dd2`](https://github.com/rust-phf/rust-phf/commit/e073dd262d1b4c95234222ee5048fc883b9c7301))
+    - Release v0.7.17 ([`21ecf72`](https://github.com/rust-phf/rust-phf/commit/21ecf72101715e4754db95a64ecd7de5a37b7f14))
+    - Merge pull request #92 from Bobo1239/master ([`d4b788d`](https://github.com/rust-phf/rust-phf/commit/d4b788dbce05fa8e103bd9d0a3022230ae738b81))
+    - Fix for latest nightly ([`cb1ec95`](https://github.com/rust-phf/rust-phf/commit/cb1ec955442750fc712d155346beeb9562905602))
+    - Merge pull request #91 from Bobo1239/master ([`bf472f2`](https://github.com/rust-phf/rust-phf/commit/bf472f2baed1552530a80c95ba5872a78fd68a5c))
+    - Remove dead code ([`df0d8e8`](https://github.com/rust-phf/rust-phf/commit/df0d8e8ae9b23482fb19ca70f1f3bd6cdfe59358))
+    - Add compile-fail test for equivalent UniCase keys ([`711515a`](https://github.com/rust-phf/rust-phf/commit/711515ad0ab53c14303b6c659a1fb3c2b3c86df5))
+    - Add UniCase support to phf_macros and bump unicase version ([`2af3abb`](https://github.com/rust-phf/rust-phf/commit/2af3abb00cafc85d43755e43767a2a8b274f6670))
+    - Merge branch 'release' ([`839f06d`](https://github.com/rust-phf/rust-phf/commit/839f06d5a10c1300353b8f3c972990624695b668))
+    - Merge branch 'release-v0.7.16' into release ([`6f5575c`](https://github.com/rust-phf/rust-phf/commit/6f5575c9b12d3619ea17c0825a613fcac12820f4))
+    - Release v0.7.16 ([`8bf29c1`](https://github.com/rust-phf/rust-phf/commit/8bf29c10a878c83d73cc40385f0e96cb9cc95afa))
+    - Merge pull request #89 from Machtan/master ([`ce387c3`](https://github.com/rust-phf/rust-phf/commit/ce387c3e2fb64ee031e812b93a64064098c5d617))
+    - Update the TokenTree import ([`f404629`](https://github.com/rust-phf/rust-phf/commit/f40462989e75ce85de8c88d6faaee934d05fe006))
+    - Merge branch 'release' ([`b4ec398`](https://github.com/rust-phf/rust-phf/commit/b4ec398f415e5cac2cd4d794b1889788e644447f))
+    - Merge branch 'release-v0.7.15' into release ([`6bbc9e2`](https://github.com/rust-phf/rust-phf/commit/6bbc9e249b9a84e2019432b7d3b178851d2d776e))
+    - Release v0.7.15 ([`20f896e`](https://github.com/rust-phf/rust-phf/commit/20f896e6975cabb9cf9883b08eaa5b3da8597f11))
+    - Merge branch 'release' ([`7c692d4`](https://github.com/rust-phf/rust-phf/commit/7c692d42970bf6cb2540f6b2d3c88d63b3fd1f7a))
+    - Merge branch 'release-v0.7.14' into release ([`ea8dd65`](https://github.com/rust-phf/rust-phf/commit/ea8dd652c292746a20bf3a680e9f925f6f0530b1))
+    - Release v0.7.14 ([`fee66fc`](https://github.com/rust-phf/rust-phf/commit/fee66fc20e33f2b119f830a8926f3b6e52abcf09))
+    - Introduce a Slice abstraction for buffers ([`0cc3844`](https://github.com/rust-phf/rust-phf/commit/0cc38449c21f29bd9348e28c5719d650e16159cf))
+    - Merge branch 'release' ([`d9351e1`](https://github.com/rust-phf/rust-phf/commit/d9351e1488bd42d1a4453e4a465177fb1c781fdc))
+    - Merge branch 'release-v0.7.13' into release ([`b582e4e`](https://github.com/rust-phf/rust-phf/commit/b582e4ecec23be992ba915fc7873c0d5598f388a))
+    - Release v0.7.13 ([`4769a6d`](https://github.com/rust-phf/rust-phf/commit/4769a6d2ce1d392da06e4b3cb833a1cdccb1f1aa))
+    - Merge pull request #80 from nox/rustup ([`6d17c1f`](https://github.com/rust-phf/rust-phf/commit/6d17c1ffe01d82eaeb0d087762c73ed6ab288bbe))
+    - Update to Rust 2016-02-22 ([`c995514`](https://github.com/rust-phf/rust-phf/commit/c9955143ffdb07bf85a525494811bd96517bf688))
+    - Merge branch 'release' ([`5659a9d`](https://github.com/rust-phf/rust-phf/commit/5659a9db39bc5ee2179b264fce4cba4384d6d025))
+    - Merge branch 'release-v0.7.12' into release ([`2f0a5de`](https://github.com/rust-phf/rust-phf/commit/2f0a5de9f01d9d22c774d8d85daec2a047a462e8))
+    - Release v0.7.12 ([`9b75ee5`](https://github.com/rust-phf/rust-phf/commit/9b75ee5ed14060c45a5785fba0387be09e698624))
+    - Merge pull request #77 from nox/byte-string-key ([`75606bc`](https://github.com/rust-phf/rust-phf/commit/75606bc371b532dddb814588bc65a9a2a5343ddb))
+    - Support byte string keys in phf_macros (fixes #76) ([`652beae`](https://github.com/rust-phf/rust-phf/commit/652beae0cac6711ab0931d8dc844cd291559dad7))
+    - Merge branch 'release' ([`87ffab8`](https://github.com/rust-phf/rust-phf/commit/87ffab863aaeefb5ac2164da62f0407122d8057e))
+    - Merge branch 'release-v0.7.11' into release ([`7260d04`](https://github.com/rust-phf/rust-phf/commit/7260d04413349bacab484afb74f9a496335278e1))
+    - Release v0.7.11 ([`a004227`](https://github.com/rust-phf/rust-phf/commit/a0042277b181ec95fcbf29751b9a453f4f962ebb))
+    - Merge pull request #74 from djudd/fix-eat-retval ([`4791e96`](https://github.com/rust-phf/rust-phf/commit/4791e9602bc00e67bc9dd22fa55a58d7609d469c))
+    - Update for changed return value of parser.eat ([`82da9f0`](https://github.com/rust-phf/rust-phf/commit/82da9f00f404634c09097f9116cda9e8e742d556))
+    - Switch timing info back to a hint ([`771e781`](https://github.com/rust-phf/rust-phf/commit/771e781e704e581c1a103f56ed0f6f2a68917883))
+    - Merge branch 'release' ([`1579bec`](https://github.com/rust-phf/rust-phf/commit/1579bec1448c7b833f5965fe39d4ef2df66c982c))
+    - Merge branch 'release-v0.7.10' into release ([`25cea13`](https://github.com/rust-phf/rust-phf/commit/25cea133fb4eec938bdfa74f04adbc8d94e30d4e))
+    - Release v0.7.10 ([`c43154b`](https://github.com/rust-phf/rust-phf/commit/c43154b2661dc09620a7879c16f37b47d6ec03ae))
+    - Update for syntax changes ([`3be2db8`](https://github.com/rust-phf/rust-phf/commit/3be2db8d9254214bf1571fafd466ed7d6b96af55))
+    - Merge branch 'release' ([`2c67ce5`](https://github.com/rust-phf/rust-phf/commit/2c67ce5a4129cd543178bf015f021a3bb83b6895))
+    - Merge branch 'release-v0.7.9' into release ([`87206e1`](https://github.com/rust-phf/rust-phf/commit/87206e1c7b8d4089370dc168402ded0c0700a447))
+    - Release v0.7.9 ([`b7d29df`](https://github.com/rust-phf/rust-phf/commit/b7d29dfe0df288b2da74de195f764eace1c8e443))
+    - Merge pull request #71 from djudd/rustc-plugin-rename ([`260437e`](https://github.com/rust-phf/rust-phf/commit/260437ee8dc5fcad43654b07ccef101089cadabd))
+    - Registry now seems to live in rustc_plugin instead of rustc::plugin ([`ba8d701`](https://github.com/rust-phf/rust-phf/commit/ba8d7019599cb779b9f7ab983f6cc2aa4f422991))
+    - Merge branch 'release' ([`cd33902`](https://github.com/rust-phf/rust-phf/commit/cd339023e90ac1ce6971fa81badea65fb1f2b086))
+    - Merge branch 'release-v0.7.8' into release ([`8bc23a0`](https://github.com/rust-phf/rust-phf/commit/8bc23a023908a038d668b6f7d8e94ee416995285))
+    - Release v0.7.8 ([`aad0b9b`](https://github.com/rust-phf/rust-phf/commit/aad0b9b658fb970e3df60b066961aafca1a17c44))
+    - Merge pull request #70 from nrc/rustup ([`2cc2ed3`](https://github.com/rust-phf/rust-phf/commit/2cc2ed36e30dea0ce0411784be87b184c0c68961))
+    - Rustup ([`a6c43fa`](https://github.com/rust-phf/rust-phf/commit/a6c43fa25e06684121df6a93b2b90405d8e0fc2e))
+    - Merge branch 'release' ([`dccff69`](https://github.com/rust-phf/rust-phf/commit/dccff69384729e3d4972174ce62d8f9db9429485))
+    - Merge branch 'release-v0.7.7' into release ([`2d988b7`](https://github.com/rust-phf/rust-phf/commit/2d988b7dfb04d949246adc047f6b195263612246))
+    - Release v0.7.7 ([`c9e7a93`](https://github.com/rust-phf/rust-phf/commit/c9e7a93f4d6f85a72651aba6187e4c956d8c1167))
+    - Merge pull request #69 from nrc/rustup ([`8185728`](https://github.com/rust-phf/rust-phf/commit/81857284f30ff832f4c8eb7c68a2957f2acdb198))
+    - Rustup for phf_macros ([`4c51ffc`](https://github.com/rust-phf/rust-phf/commit/4c51ffc6d63f768dea75cab65ad6cb809bce9bb4))
+    - Run through rustfmt ([`58e2223`](https://github.com/rust-phf/rust-phf/commit/58e222380b7fc9609a055cb5a6110ba04e47d677))
+    - Merge branch 'release' ([`776046c`](https://github.com/rust-phf/rust-phf/commit/776046c961456dee9e16a6b6574d336c66e259f8))
+    - Merge branch 'release-v0.7.6' into release ([`2ea7d5c`](https://github.com/rust-phf/rust-phf/commit/2ea7d5cab5e9e54952ca618b43ec3583a33a4847))
+    - Release v0.7.6 ([`5bcd5c9`](https://github.com/rust-phf/rust-phf/commit/5bcd5c95215f5aa29e133cb2912662085a8158f0))
+    - Merge branch 'release' ([`1f770df`](https://github.com/rust-phf/rust-phf/commit/1f770df1290b586a8d641ecb0bbd105080afc0ea))
+    - Merge branch 'release-v0.7.5' into release ([`bb65b8c`](https://github.com/rust-phf/rust-phf/commit/bb65b8cca30ef9d4518e3083558019a972873efa))
+    - Release v0.7.5 ([`fda44f5`](https://github.com/rust-phf/rust-phf/commit/fda44f550401c1bd4aad29bb2c07030b86761028))
+    - Merge pull request #65 from dinfuehr/master ([`fc1f6b0`](https://github.com/rust-phf/rust-phf/commit/fc1f6b00c5aeb00b1d1e5d418b5979c7cb8b8afd))
+    - Update code for changes in Rust ([`8225c4b`](https://github.com/rust-phf/rust-phf/commit/8225c4b90d6ee71483304e71342c269fca86a044))
+    - Macro assemble benchmark map and match to ensure sync ([`a2486ed`](https://github.com/rust-phf/rust-phf/commit/a2486eda19c647d16c9976bb33ba8634388a0569))
+    - Merge pull request #63 from erickt/master ([`e879788`](https://github.com/rust-phf/rust-phf/commit/e8797888ff6f1a7a690a44844b692107cbf2c8a9))
+    - Add benchmarks ([`9585cc3`](https://github.com/rust-phf/rust-phf/commit/9585cc3c0391725d02f6199eaed500ba5fafcaf3))
+    - Merge branch 'release' ([`269b5dc`](https://github.com/rust-phf/rust-phf/commit/269b5dc41ebf82f423393d5219e8107e9c911a03))
+    - Merge branch 'release-v0.7.4' into release ([`7c093e8`](https://github.com/rust-phf/rust-phf/commit/7c093e83ffe5192d9cdcd5402b6abb7800ffafb3))
+    - Release v0.7.4 ([`c7c0d3c`](https://github.com/rust-phf/rust-phf/commit/c7c0d3c294126157f0275a05b7c3a65c419234a1))
+    - Update PhfHash to mirror std::hash::Hash ([`96ef156`](https://github.com/rust-phf/rust-phf/commit/96ef156baae669b233673d6be2b96617ad48551e))
+    - Release v0.7.3 ([`77ea239`](https://github.com/rust-phf/rust-phf/commit/77ea23917e908b10c4c5c463671a8409292f8661))
+    - Release v0.7.2 ([`642b69d`](https://github.com/rust-phf/rust-phf/commit/642b69d0100a4ee7ec6e430ef1351bd1f28f9a4a))
+    - Add an index test ([`f51f449`](https://github.com/rust-phf/rust-phf/commit/f51f449261ddd8ad30bfb5507b166e7980df1aa7))
+    - Release v0.7.1 ([`9cb9de9`](https://github.com/rust-phf/rust-phf/commit/9cb9de911ad4e16964f0def29780dde1630c3619))
+    - Fix phf-macros ([`6c98e9f`](https://github.com/rust-phf/rust-phf/commit/6c98e9f16a6d9ebf11e0a9c8e9ff91b4b320d2af))
+    - Release v0.7.0 ([`555a690`](https://github.com/rust-phf/rust-phf/commit/555a690561673597aee068650ac884bbcc2e31cf))
+    - Stabilize phf ([`e215273`](https://github.com/rust-phf/rust-phf/commit/e2152739cbdd471116d88bb4a9cea4cdfede1e42))
+    - Release v0.6.19 ([`5810d30`](https://github.com/rust-phf/rust-phf/commit/5810d30ef2162f33cfb4da99c65b7344c7f2913b))
+    - Release v0.6.18 ([`36efc72`](https://github.com/rust-phf/rust-phf/commit/36efc721478d097fba1e5458cbdd9f288637abae))
+    - Fix for upstream changes ([`eabadcf`](https://github.com/rust-phf/rust-phf/commit/eabadcf7e8af351ba8f07d86746e35adc8c5812e))
+    - Release v0.6.17 ([`271ccc2`](https://github.com/rust-phf/rust-phf/commit/271ccc27d885363d4d8c549f75624d08c48e56c5))
+    - Release v0.6.15 ([`ede14df`](https://github.com/rust-phf/rust-phf/commit/ede14df1e574674852b09bcafff4ad549ebfd4ae))
+    - Remove broken test ([`f54adb7`](https://github.com/rust-phf/rust-phf/commit/f54adb783a71678c9397b4d7c1e02ee82b9646b8))
+    - Release v0.6.14 ([`cf64ebb`](https://github.com/rust-phf/rust-phf/commit/cf64ebb8f769c9f12c9a03d05713dde6b8caf371))
+    - Release v0.6.13 ([`4fdb533`](https://github.com/rust-phf/rust-phf/commit/4fdb5331fd9978ca3e180a06fb2e34627f50fb77))
+    - Fix warnings and use debug builders ([`4d28684`](https://github.com/rust-phf/rust-phf/commit/4d28684b72333e911e23b898b5780947d49822a5))
+    - Release v0.6.12 ([`59ca586`](https://github.com/rust-phf/rust-phf/commit/59ca58637206c9806c13cc24cb35cb7d0ce9d23f))
+    - Fix phf_macros ([`6567152`](https://github.com/rust-phf/rust-phf/commit/6567152be9e018a99fedf6e54017d827812b8f13))
+    - Release v0.6.11 ([`e1e6d3b`](https://github.com/rust-phf/rust-phf/commit/e1e6d3b40a6babddd0989406f2b4e952443ff52e))
+    - Release v0.6.10 ([`fc45373`](https://github.com/rust-phf/rust-phf/commit/fc45373b34a461664f532c5108f3d2625172c128))
+    - Add doc URLs ([`4605db3`](https://github.com/rust-phf/rust-phf/commit/4605db3e7e0c4bef09ccf6c09c7dbcc36b707a9f))
+    - Add documentation for phf_macros ([`8eca797`](https://github.com/rust-phf/rust-phf/commit/8eca79711f33d04ad773a023581b6bd0a6f1efdc))
+    - Move generation logic to its own crate ([`cfeee87`](https://github.com/rust-phf/rust-phf/commit/cfeee8714caa4ecb3199df2a2ac149fe6a28ecc0))
+    - Move tests to phf_macros ([`40dbc32`](https://github.com/rust-phf/rust-phf/commit/40dbc328456003484716021cc317156967f1b2c1))
+    - Release v0.6.9 ([`822f4e3`](https://github.com/rust-phf/rust-phf/commit/822f4e3fb127dc02d36d802803d71aa5b98bed3c))
+    - More fixes ([`0c04b9c`](https://github.com/rust-phf/rust-phf/commit/0c04b9cb2679a63394778a7362ef14441b6c2032))
+    - Release v0.6.8 ([`cd637ca`](https://github.com/rust-phf/rust-phf/commit/cd637cafb6d37b1901b6c119a7d26f253e9a288e))
+    - Release v0.6.7 ([`bfc36c9`](https://github.com/rust-phf/rust-phf/commit/bfc36c979225f652cdb72f3b1f2a25e77b50ab8c))
+    - Fix for upstream changes ([`5ff7040`](https://github.com/rust-phf/rust-phf/commit/5ff70403a1b12c30206b128ac619b31c69e42eb4))
+    - Merge pull request #47 from globin/fix/rustup ([`5aac93b`](https://github.com/rust-phf/rust-phf/commit/5aac93bad40ccac195e1f66614a29a9240dcaf54))
+    - Rustup to current master ([`f6922e2`](https://github.com/rust-phf/rust-phf/commit/f6922e245752b4932f9a3a420c1f8d10e66e0b78))
+    - Release v0.6.6 ([`b09a174`](https://github.com/rust-phf/rust-phf/commit/b09a174a166c7744c5989bedc6ba68340f6f7fd1))
+    - Release v0.6.5 ([`271e784`](https://github.com/rust-phf/rust-phf/commit/271e7848f35b31d6ce9fc9268de173738464bfc8))
+    - Move docs to this repo and auto build them ([`f8ef160`](https://github.com/rust-phf/rust-phf/commit/f8ef160480e2d4ce72fa7afb6ebce70e45acbc76))
+    - Release v0.6.4 ([`6866c1b`](https://github.com/rust-phf/rust-phf/commit/6866c1bf5ad5091bc969f1356884aa86c27458cb))
+    - Remove unused feature ([`2ee5f78`](https://github.com/rust-phf/rust-phf/commit/2ee5f788d493d929b669550c144ff23aad52721b))
+    - Merge pull request #45 from Manishearth/internedstring ([`9b9c009`](https://github.com/rust-phf/rust-phf/commit/9b9c00934e33d920ab287765458d26ab321d8ab4))
+    - InternedString.get() removal; brings us to rustc 1.0.0-dev (80627cd3c 2015-02-07 12:01:31 +0000) ([`3150bf0`](https://github.com/rust-phf/rust-phf/commit/3150bf0d608b051f2c8db3826ee21ce593f4f61c))
+    - Release v0.6.3 ([`b0c5e3c`](https://github.com/rust-phf/rust-phf/commit/b0c5e3cb69742f81160ea80a3ba1782a0b4e01a2))
+    - Use out of tree rand ([`9e1623b`](https://github.com/rust-phf/rust-phf/commit/9e1623bc7d1b8a432cdae47187eab40fa168401f))
+    - Release v0.6.2 ([`d9ddf45`](https://github.com/rust-phf/rust-phf/commit/d9ddf45b15ba812b0d3acedffb08e901742e56c4))
+    - Release v0.6.1 ([`ca0e9f6`](https://github.com/rust-phf/rust-phf/commit/ca0e9f6b9c737f3d11bcad2f4624bb5603a8170e))
+    - Fix for stability changes ([`f7fb510`](https://github.com/rust-phf/rust-phf/commit/f7fb510dfe67f11522a2d214bd14d21f910bfd7b))
+    - Release v0.6.0 ([`09d6870`](https://github.com/rust-phf/rust-phf/commit/09d687053caf4d321f72907528573b3334fae3c2))
+    - Rename phf_mac to phf_macros ([`c50d107`](https://github.com/rust-phf/rust-phf/commit/c50d1077b1d53fccd703021911a7100b8937bbc7))
+</details>
+
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.lock b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.lock
new file mode 100644
index 000000000000..5f6114ecca75
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.lock
@@ -0,0 +1,97 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "phf_generator"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c80231409c20246a13fddb31776fb942c38553c51e871f8cbd687a4cfb5843d"
+dependencies = [
+ "phf_shared",
+ "rand",
+]
+
+[[package]]
+name = "phf_macros"
+version = "0.11.3"
+dependencies = [
+ "phf_generator",
+ "phf_shared",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "unicase",
+]
+
+[[package]]
+name = "phf_shared"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67eabc2ef2a60eb7faa00097bd1ffdb5bd28e62bf39990626a582201b7a754e5"
+dependencies = [
+ "siphasher",
+ "unicase",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.38"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e4dccaaaf89514f546c693ddc140f729f958c247918a13380cccc6078391acc"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+
+[[package]]
+name = "siphasher"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56199f7ddabf13fe5074ce809e7d3f42b42ae711800501b5b16ea82ad029c39d"
+
+[[package]]
+name = "syn"
+version = "2.0.95"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46f71c0377baf4ef1cc3e3402ded576dccc315800fbc62dfc7fe04b009773b4a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicase"
+version = "2.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75b844d17643ee918803943289730bec8aac480150456169e647ed0b576ba539"
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adb9e6ca4f869e1180728b7950e35922a7fc6397f7b641499e8f3ef06e50dc83"
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml
new file mode 100644
index 000000000000..afdb3663ba4c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml
@@ -0,0 +1,62 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+rust-version = "1.61"
+name = "phf_macros"
+version = "0.11.3"
+authors = ["Steven Fackler <sfackler@gmail.com>"]
+build = false
+autolib = false
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "Macros to generate types in the phf crate"
+readme = "README.md"
+categories = ["data-structures"]
+license = "MIT"
+repository = "https://github.com/rust-phf/rust-phf"
+resolver = "1"
+
+[lib]
+name = "phf_macros"
+path = "src/lib.rs"
+proc-macro = true
+
+[dependencies.phf_generator]
+version = "0.11.1"
+
+[dependencies.phf_shared]
+version = "^0.11.2"
+default-features = false
+
+[dependencies.proc-macro2]
+version = "1"
+
+[dependencies.quote]
+version = "1"
+
+[dependencies.syn]
+version = "2"
+features = ["full"]
+
+[dependencies.unicase_]
+version = "2.4.0"
+optional = true
+package = "unicase"
+
+[features]
+unicase = [
+    "unicase_",
+    "phf_shared/unicase",
+]
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml.orig
new file mode 100644
index 000000000000..db28c09d80ce
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/Cargo.toml.orig
@@ -0,0 +1,26 @@
+[package]
+name = "phf_macros"
+version = "0.11.3"
+authors = ["Steven Fackler <sfackler@gmail.com>"]
+edition = "2021"
+license = "MIT"
+description = "Macros to generate types in the phf crate"
+repository = "https://github.com/rust-phf/rust-phf"
+readme = "../README.md"
+rust-version = "1.61"
+categories = ["data-structures"]
+
+[lib]
+proc-macro = true
+
+[features]
+unicase = ["unicase_", "phf_shared/unicase"]
+
+[dependencies]
+syn = { version = "2", features = ["full"] }
+quote = "1"
+proc-macro2 = "1"
+unicase_ = { package = "unicase", version = "2.4.0", optional = true }
+
+phf_generator = "0.11.1"
+phf_shared = { version = "^0.11.2", default-features = false }
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/LICENSE b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/LICENSE
new file mode 100644
index 000000000000..cd5bf6855b57
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014-2022 Steven Fackler, Yuki Okushi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/README.md b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/README.md
new file mode 100644
index 000000000000..f41d379b081e
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/README.md
@@ -0,0 +1,127 @@
+# Rust-PHF
+
+[![CI](https://github.com/rust-phf/rust-phf/actions/workflows/ci.yml/badge.svg)](https://github.com/rust-phf/rust-phf/actions/workflows/ci.yml) [![Latest Version](https://img.shields.io/crates/v/phf.svg)](https://crates.io/crates/phf)
+
+[Documentation](https://docs.rs/phf)
+
+Rust-PHF is a library to generate efficient lookup tables at compile time using
+[perfect hash functions](http://en.wikipedia.org/wiki/Perfect_hash_function).
+
+It currently uses the
+[CHD algorithm](http://cmph.sourceforge.net/papers/esa09.pdf) and can generate
+a 100,000 entry map in roughly .4 seconds.
+
+MSRV (minimum supported rust version) is Rust 1.61.
+
+## Usage
+
+PHF data structures can be constructed via either the procedural
+macros in the `phf_macros` crate or code generation supported by the
+`phf_codegen` crate.
+
+To compile the `phf` crate with a dependency on
+libcore instead of libstd, enabling use in environments where libstd
+will not work, set `default-features = false` for the dependency:
+
+```toml
+[dependencies]
+# to use `phf` in `no_std` environments
+phf = { version = "0.11", default-features = false }
+```
+
+### phf_macros
+
+```rust
+use phf::phf_map;
+
+#[derive(Clone)]
+pub enum Keyword {
+    Loop,
+    Continue,
+    Break,
+    Fn,
+    Extern,
+}
+
+static KEYWORDS: phf::Map<&'static str, Keyword> = phf_map! {
+    "loop" => Keyword::Loop,
+    "continue" => Keyword::Continue,
+    "break" => Keyword::Break,
+    "fn" => Keyword::Fn,
+    "extern" => Keyword::Extern,
+};
+
+pub fn parse_keyword(keyword: &str) -> Option<Keyword> {
+    KEYWORDS.get(keyword).cloned()
+}
+```
+
+```toml
+[dependencies]
+phf = { version = "0.11", features = ["macros"] }
+```
+
+#### Note
+
+Currently, the macro syntax has some limitations and may not
+work as you want. See [#183] or [#196] for example.
+
+[#183]: https://github.com/rust-phf/rust-phf/issues/183
+[#196]: https://github.com/rust-phf/rust-phf/issues/196
+
+### phf_codegen
+
+To use `phf_codegen` on build.rs, you have to add dependencies under `[build-dependencies]`:
+
+```toml
+[build-dependencies]
+phf = { version = "0.11.1", default-features = false }
+phf_codegen = "0.11.1"
+```
+
+Then put code on build.rs:
+
+```rust
+use std::env;
+use std::fs::File;
+use std::io::{BufWriter, Write};
+use std::path::Path;
+
+fn main() {
+    let path = Path::new(&env::var("OUT_DIR").unwrap()).join("codegen.rs");
+    let mut file = BufWriter::new(File::create(&path).unwrap());
+
+    write!(
+        &mut file,
+        "static KEYWORDS: phf::Map<&'static str, Keyword> = {}",
+        phf_codegen::Map::new()
+            .entry("loop", "Keyword::Loop")
+            .entry("continue", "Keyword::Continue")
+            .entry("break", "Keyword::Break")
+            .entry("fn", "Keyword::Fn")
+            .entry("extern", "Keyword::Extern")
+            .build()
+    )
+    .unwrap();
+    write!(&mut file, ";\n").unwrap();
+}
+```
+
+and lib.rs:
+
+```rust
+#[derive(Clone)]
+enum Keyword {
+    Loop,
+    Continue,
+    Break,
+    Fn,
+    Extern,
+}
+
+include!(concat!(env!("OUT_DIR"), "/codegen.rs"));
+
+pub fn parse_keyword(keyword: &str) -> Option<Keyword> {
+    KEYWORDS.get(keyword).cloned()
+}
+```
diff --git a/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs
new file mode 100644
index 000000000000..e942a9ebca10
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs
@@ -0,0 +1,338 @@
+//! A set of macros to generate Rust source for PHF data structures at compile time.
+//! See [the `phf` crate's documentation][phf] for details.
+//!
+//! [phf]: https://docs.rs/phf
+
+use phf_generator::HashState;
+use phf_shared::PhfHash;
+use proc_macro::TokenStream;
+use quote::quote;
+use std::collections::HashSet;
+use std::hash::Hasher;
+use syn::parse::{self, Parse, ParseStream};
+use syn::punctuated::Punctuated;
+use syn::{parse_macro_input, Error, Expr, ExprLit, Lit, Token, UnOp};
+#[cfg(feature = "unicase")]
+use unicase_::UniCase;
+
+#[derive(Hash, PartialEq, Eq, Clone)]
+enum ParsedKey {
+    Str(String),
+    Binary(Vec<u8>),
+    Char(char),
+    I8(i8),
+    I16(i16),
+    I32(i32),
+    I64(i64),
+    I128(i128),
+    Isize(isize),
+    U8(u8),
+    U16(u16),
+    U32(u32),
+    U64(u64),
+    U128(u128),
+    Usize(usize),
+    Bool(bool),
+    #[cfg(feature = "unicase")]
+    UniCase(UniCase<String>),
+}
+
+impl PhfHash for ParsedKey {
+    fn phf_hash<H>(&self, state: &mut H)
+    where
+        H: Hasher,
+    {
+        match self {
+            ParsedKey::Str(s) => s.phf_hash(state),
+            ParsedKey::Binary(s) => s.phf_hash(state),
+            ParsedKey::Char(s) => s.phf_hash(state),
+            ParsedKey::I8(s) => s.phf_hash(state),
+            ParsedKey::I16(s) => s.phf_hash(state),
+            ParsedKey::I32(s) => s.phf_hash(state),
+            ParsedKey::I64(s) => s.phf_hash(state),
+            ParsedKey::I128(s) => s.phf_hash(state),
+            ParsedKey::Isize(s) => s.phf_hash(state),
+            ParsedKey::U8(s) => s.phf_hash(state),
+            ParsedKey::U16(s) => s.phf_hash(state),
+            ParsedKey::U32(s) => s.phf_hash(state),
+            ParsedKey::U64(s) => s.phf_hash(state),
+            ParsedKey::U128(s) => s.phf_hash(state),
+            ParsedKey::Usize(s) => s.phf_hash(state),
+            ParsedKey::Bool(s) => s.phf_hash(state),
+            #[cfg(feature = "unicase")]
+            ParsedKey::UniCase(s) => s.phf_hash(state),
+        }
+    }
+}
+
+impl ParsedKey {
+    fn from_expr(expr: &Expr) -> Option<ParsedKey> {
+        match expr {
+            Expr::Lit(lit) => match &lit.lit {
+                Lit::Str(s) => Some(ParsedKey::Str(s.value())),
+                Lit::ByteStr(s) => Some(ParsedKey::Binary(s.value())),
+                Lit::Byte(s) => Some(ParsedKey::U8(s.value())),
+                Lit::Char(s) => Some(ParsedKey::Char(s.value())),
+                Lit::Int(s) => match s.suffix() {
+                    // we've lost the sign at this point, so `-128i8` looks like `128i8`,
+                    // which doesn't fit in an `i8`; parse it as a `u8` and cast (to `0i8`),
+                    // which is handled below, by `Unary`
+                    "i8" => Some(ParsedKey::I8(s.base10_parse::<u8>().unwrap() as i8)),
+                    "i16" => Some(ParsedKey::I16(s.base10_parse::<u16>().unwrap() as i16)),
+                    "i32" => Some(ParsedKey::I32(s.base10_parse::<u32>().unwrap() as i32)),
+                    "i64" => Some(ParsedKey::I64(s.base10_parse::<u64>().unwrap() as i64)),
+                    "i128" => Some(ParsedKey::I128(s.base10_parse::<u128>().unwrap() as i128)),
+                    "isize" => Some(ParsedKey::Isize(s.base10_parse::<usize>().unwrap() as isize)),
+                    "u8" => Some(ParsedKey::U8(s.base10_parse::<u8>().unwrap())),
+                    "u16" => Some(ParsedKey::U16(s.base10_parse::<u16>().unwrap())),
+                    "u32" => Some(ParsedKey::U32(s.base10_parse::<u32>().unwrap())),
+                    "u64" => Some(ParsedKey::U64(s.base10_parse::<u64>().unwrap())),
+                    "u128" => Some(ParsedKey::U128(s.base10_parse::<u128>().unwrap())),
+                    "usize" => Some(ParsedKey::Usize(s.base10_parse::<usize>().unwrap())),
+                    _ => None,
+                },
+                Lit::Bool(s) => Some(ParsedKey::Bool(s.value)),
+                _ => None,
+            },
+            Expr::Array(array) => {
+                let mut buf = vec![];
+                for expr in &array.elems {
+                    match expr {
+                        Expr::Lit(lit) => match &lit.lit {
+                            Lit::Int(s) => match s.suffix() {
+                                "u8" | "" => buf.push(s.base10_parse::<u8>().unwrap()),
+                                _ => return None,
+                            },
+                            _ => return None,
+                        },
+                        _ => return None,
+                    }
+                }
+                Some(ParsedKey::Binary(buf))
+            }
+            Expr::Unary(unary) => {
+                // if we received an integer literal (always unsigned) greater than i__::max_value()
+                // then casting it to a signed integer type of the same width will negate it to
+                // the same absolute value so we don't need to negate it here
+                macro_rules! try_negate (
+                    ($val:expr) => {if $val < 0 { $val } else { -$val }}
+                );
+
+                match unary.op {
+                    UnOp::Neg(_) => match ParsedKey::from_expr(&unary.expr)? {
+                        ParsedKey::I8(v) => Some(ParsedKey::I8(try_negate!(v))),
+                        ParsedKey::I16(v) => Some(ParsedKey::I16(try_negate!(v))),
+                        ParsedKey::I32(v) => Some(ParsedKey::I32(try_negate!(v))),
+                        ParsedKey::I64(v) => Some(ParsedKey::I64(try_negate!(v))),
+                        ParsedKey::I128(v) => Some(ParsedKey::I128(try_negate!(v))),
+                        ParsedKey::Isize(v) => Some(ParsedKey::Isize(try_negate!(v))),
+                        _ => None,
+                    },
+                    UnOp::Deref(_) => {
+                        let mut expr = &*unary.expr;
+                        while let Expr::Group(group) = expr {
+                            expr = &*group.expr;
+                        }
+                        match expr {
+                            Expr::Lit(ExprLit {
+                                lit: Lit::ByteStr(s),
+                                ..
+                            }) => Some(ParsedKey::Binary(s.value())),
+                            _ => None,
+                        }
+                    }
+                    _ => None,
+                }
+            }
+            Expr::Group(group) => ParsedKey::from_expr(&group.expr),
+            #[cfg(feature = "unicase")]
+            Expr::Call(call) => {
+                if let Expr::Path(ep) = call.func.as_ref() {
+                    let segments = &mut ep.path.segments.iter().rev();
+                    let last = &segments.next()?.ident;
+                    let last_ahead = &segments.next()?.ident;
+                    let is_unicode = last_ahead == "UniCase" && last == "unicode";
+                    let is_ascii = last_ahead == "UniCase" && last == "ascii";
+                    if call.args.len() == 1 && (is_unicode || is_ascii) {
+                        if let Some(Expr::Lit(ExprLit {
+                            attrs: _,
+                            lit: Lit::Str(s),
+                        })) = call.args.first()
+                        {
+                            let v = if is_unicode {
+                                UniCase::unicode(s.value())
+                            } else {
+                                UniCase::ascii(s.value())
+                            };
+                            Some(ParsedKey::UniCase(v))
+                        } else {
+                            None
+                        }
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        }
+    }
+}
+
+struct Key {
+    parsed: ParsedKey,
+    expr: Expr,
+}
+
+impl PhfHash for Key {
+    fn phf_hash<H>(&self, state: &mut H)
+    where
+        H: Hasher,
+    {
+        self.parsed.phf_hash(state)
+    }
+}
+
+impl Parse for Key {
+    fn parse(input: ParseStream<'_>) -> parse::Result<Key> {
+        let expr = input.parse()?;
+        let parsed = ParsedKey::from_expr(&expr)
+            .ok_or_else(|| Error::new_spanned(&expr, "unsupported key expression"))?;
+
+        Ok(Key { parsed, expr })
+    }
+}
+
+struct Entry {
+    key: Key,
+    value: Expr,
+}
+
+impl PhfHash for Entry {
+    fn phf_hash<H>(&self, state: &mut H)
+    where
+        H: Hasher,
+    {
+        self.key.phf_hash(state)
+    }
+}
+
+impl Parse for Entry {
+    fn parse(input: ParseStream<'_>) -> parse::Result<Entry> {
+        let key = input.parse()?;
+        input.parse::<Token![=>]>()?;
+        let value = input.parse()?;
+        Ok(Entry { key, value })
+    }
+}
+
+struct Map(Vec<Entry>);
+
+impl Parse for Map {
+    fn parse(input: ParseStream<'_>) -> parse::Result<Map> {
+        let parsed = Punctuated::<Entry, Token![,]>::parse_terminated(input)?;
+        let map = parsed.into_iter().collect::<Vec<_>>();
+        check_duplicates(&map)?;
+        Ok(Map(map))
+    }
+}
+
+struct Set(Vec<Entry>);
+
+impl Parse for Set {
+    fn parse(input: ParseStream<'_>) -> parse::Result<Set> {
+        let parsed = Punctuated::<Key, Token![,]>::parse_terminated(input)?;
+        let set = parsed
+            .into_iter()
+            .map(|key| Entry {
+                key,
+                value: syn::parse_str("()").unwrap(),
+            })
+            .collect::<Vec<_>>();
+        check_duplicates(&set)?;
+        Ok(Set(set))
+    }
+}
+
+fn check_duplicates(entries: &[Entry]) -> parse::Result<()> {
+    let mut keys = HashSet::new();
+    for entry in entries {
+        if !keys.insert(&entry.key.parsed) {
+            return Err(Error::new_spanned(&entry.key.expr, "duplicate key"));
+        }
+    }
+    Ok(())
+}
+
+fn build_map(entries: &[Entry], state: HashState) -> proc_macro2::TokenStream {
+    let key = state.key;
+    let disps = state.disps.iter().map(|&(d1, d2)| quote!((#d1, #d2)));
+    let entries = state.map.iter().map(|&idx| {
+        let key = &entries[idx].key.expr;
+        let value = &entries[idx].value;
+        quote!((#key, #value))
+    });
+
+    quote! {
+        phf::Map {
+            key: #key,
+            disps: &[#(#disps),*],
+            entries: &[#(#entries),*],
+        }
+    }
+}
+
+fn build_ordered_map(entries: &[Entry], state: HashState) -> proc_macro2::TokenStream {
+    let key = state.key;
+    let disps = state.disps.iter().map(|&(d1, d2)| quote!((#d1, #d2)));
+    let idxs = state.map.iter().map(|idx| quote!(#idx));
+    let entries = entries.iter().map(|entry| {
+        let key = &entry.key.expr;
+        let value = &entry.value;
+        quote!((#key, #value))
+    });
+
+    quote! {
+        phf::OrderedMap {
+            key: #key,
+            disps: &[#(#disps),*],
+            idxs: &[#(#idxs),*],
+            entries: &[#(#entries),*],
+        }
+    }
+}
+
+#[proc_macro]
+pub fn phf_map(input: TokenStream) -> TokenStream {
+    let map = parse_macro_input!(input as Map);
+    let state = phf_generator::generate_hash(&map.0);
+
+    build_map(&map.0, state).into()
+}
+
+#[proc_macro]
+pub fn phf_set(input: TokenStream) -> TokenStream {
+    let set = parse_macro_input!(input as Set);
+    let state = phf_generator::generate_hash(&set.0);
+
+    let map = build_map(&set.0, state);
+    quote!(phf::Set { map: #map }).into()
+}
+
+#[proc_macro]
+pub fn phf_ordered_map(input: TokenStream) -> TokenStream {
+    let map = parse_macro_input!(input as Map);
+    let state = phf_generator::generate_hash(&map.0);
+
+    build_ordered_map(&map.0, state).into()
+}
+
+#[proc_macro]
+pub fn phf_ordered_set(input: TokenStream) -> TokenStream {
+    let set = parse_macro_input!(input as Set);
+    let state = phf_generator::generate_hash(&set.0);
+
+    let map = build_ordered_map(&set.0, state);
+    quote!(phf::OrderedSet { map: #map }).into()
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo_vcs_info.json
new file mode 100644
index 000000000000..0e7d3cd1eb89
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
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+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
+[[package]]
+name = "zerocopy"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
+dependencies = [
+ "byteorder",
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml
new file mode 100644
index 000000000000..c40c50182a2f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml
@@ -0,0 +1,84 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "scraper"
+version = "0.22.0"
+authors = ["June McEnroe <june@causal.agency>"]
+build = false
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "HTML parsing and querying with CSS selectors"
+readme = "README.md"
+keywords = [
+    "html",
+    "css",
+    "selector",
+    "scraping",
+]
+license = "ISC"
+repository = "https://github.com/causal-agent/scraper"
+
+[lib]
+name = "scraper"
+path = "src/lib.rs"
+
+[[bin]]
+name = "scraper"
+path = "src/main.rs"
+required-features = ["main"]
+
+[[example]]
+name = "document"
+path = "examples/document.rs"
+
+[[example]]
+name = "fragment"
+path = "examples/fragment.rs"
+
+[dependencies.cssparser]
+version = "0.34.0"
+
+[dependencies.ego-tree]
+version = "0.10.0"
+
+[dependencies.getopts]
+version = "0.2.21"
+optional = true
+
+[dependencies.html5ever]
+version = "0.29.0"
+
+[dependencies.indexmap]
+version = "2.7.0"
+optional = true
+
+[dependencies.precomputed-hash]
+version = "0.1.1"
+
+[dependencies.selectors]
+version = "0.26.0"
+
+[dependencies.tendril]
+version = "0.4.3"
+
+[features]
+atomic = []
+default = [
+    "main",
+    "errors",
+]
+deterministic = ["indexmap"]
+errors = []
+main = ["getopts"]
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml.orig
new file mode 100644
index 000000000000..b862c7c76829
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/Cargo.toml.orig
@@ -0,0 +1,38 @@
+[package]
+name = "scraper"
+version = "0.22.0"
+edition = "2021"
+
+description = "HTML parsing and querying with CSS selectors"
+keywords = ["html", "css", "selector", "scraping"]
+
+authors = ["June McEnroe <june@causal.agency>"]
+license = "ISC"
+
+repository = "https://github.com/causal-agent/scraper"
+readme = "README.md"
+
+[dependencies]
+cssparser = "0.34.0"
+ego-tree = "0.10.0"
+html5ever = "0.29.0"
+indexmap = { version = "2.7.0", optional = true }
+precomputed-hash = "0.1.1"
+selectors = "0.26.0"
+tendril = "0.4.3"
+
+[dependencies.getopts]
+version = "0.2.21"
+optional = true
+
+[features]
+default = ["main", "errors"]
+deterministic = ["indexmap"]
+main = ["getopts"]
+atomic = []
+errors = []
+
+[[bin]]
+name = "scraper"
+path = "src/main.rs"
+required-features = ["main"]
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/LICENSE b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/LICENSE
new file mode 100644
index 000000000000..f096bf2e2f97
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/LICENSE
@@ -0,0 +1 @@
+./../LICENSE
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/README.md b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/README.md
new file mode 100644
index 000000000000..3dfb7d794da3
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/README.md
@@ -0,0 +1 @@
+./../README.md
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/document.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/document.rs
new file mode 100644
index 000000000000..65e44b8ff7d0
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/document.rs
@@ -0,0 +1,28 @@
+extern crate scraper;
+
+use std::io::{self, Read, Write};
+
+use scraper::{Html, Selector};
+
+fn main() {
+    let mut input = String::new();
+    let mut stdout = io::stdout();
+    let mut stdin = io::stdin();
+
+    write!(stdout, "CSS selector: ").unwrap();
+    stdout.flush().unwrap();
+    stdin.read_line(&mut input).unwrap();
+    let selector = Selector::parse(&input).unwrap();
+
+    writeln!(stdout, "HTML document:").unwrap();
+    stdout.flush().unwrap();
+    input.clear();
+    stdin.read_to_string(&mut input).unwrap();
+    let document = Html::parse_document(&input);
+
+    println!("{:#?}", document);
+
+    for node in document.select(&selector) {
+        println!("{:?}", node.value());
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/fragment.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/fragment.rs
new file mode 100644
index 000000000000..1fb269011735
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/examples/fragment.rs
@@ -0,0 +1,28 @@
+extern crate scraper;
+
+use std::io::{self, Read, Write};
+
+use scraper::{Html, Selector};
+
+fn main() {
+    let mut input = String::new();
+    let mut stdout = io::stdout();
+    let mut stdin = io::stdin();
+
+    write!(stdout, "CSS selector: ").unwrap();
+    stdout.flush().unwrap();
+    stdin.read_line(&mut input).unwrap();
+    let selector = Selector::parse(&input).unwrap();
+
+    writeln!(stdout, "HTML fragment:").unwrap();
+    stdout.flush().unwrap();
+    input.clear();
+    stdin.read_to_string(&mut input).unwrap();
+    let fragment = Html::parse_fragment(&input);
+
+    println!("{:#?}", fragment);
+
+    for node in fragment.select(&selector) {
+        println!("{:?}", node.value());
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/scraper.1 b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/scraper.1
new file mode 100644
index 000000000000..d4c377fcd8ab
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/scraper.1
@@ -0,0 +1,72 @@
+.Dd October 29, 2018
+.Dt SCRAPER 1
+.Os
+.
+.Sh NAME
+.Nm scraper
+.Nd HTML querying with CSS selectors
+.
+.Sh SYNOPSIS
+.Nm
+.Op Fl HIcint
+.Op Fl a Ar attr
+.Op Fl d | f
+.Ar selector
+.Op Ar
+.
+.Sh DESCRIPTION
+The
+.Nm
+utility parses HTML and outputs elements matching CSS selectors.
+.
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.
+.It Fl H , Fl \-html
+Output the HTML of the matching elements.
+This is the default.
+.
+.It Fl I , Fl \-inner\-html
+Output the inner HTML of the matching elements.
+.
+.It Fl a Ar attr , Fl \-attr Ar attr
+Output the value of the attribute
+.Ar attr
+of the matching elements.
+.
+.It Fl c , Fl \-classes
+Output the classes of the matching elements.
+.
+.It Fl d , Fl \-document
+Parse the input as HTML documents.
+This is the default.
+.
+.It Fl f , Fl \-fragment
+Parse the input as HTML fragments.
+.
+.It Fl i , Fl \-id
+Output the IDs of the matching elements.
+.
+.It Fl n , Fl \-name
+Output the names of the matching elements.
+.
+.It Fl t , Fl \-text
+Output the text of the matching elements.
+.El
+.
+.Sh EXIT STATUS
+The
+.Nm
+utility exits 0 on success,
+1 if no elements match,
+and >1 if an error occurs.
+.
+.Sh AUTHORS
+.An June McEnroe Aq Mt june@causal.agency
+.An Vivek Kushwaha Aq Mt yoursvivek@gmail.com
+.Pp
+The
+.Nm
+utility relies heavily on code from the
+.Lk https://servo.org "Servo project" .
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/element.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/element.rs
new file mode 100644
index 000000000000..23d2a16e8545
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/element.rs
@@ -0,0 +1,212 @@
+use html5ever::Namespace;
+use selectors::{
+    attr::{AttrSelectorOperation, CaseSensitivity, NamespaceConstraint},
+    bloom::BloomFilter,
+    matching, Element, OpaqueElement,
+};
+
+use super::ElementRef;
+use crate::selector::{CssLocalName, CssString, NonTSPseudoClass, PseudoElement, Simple};
+
+/// Note: will never match against non-tree-structure pseudo-classes.
+impl Element for ElementRef<'_> {
+    type Impl = Simple;
+
+    fn opaque(&self) -> OpaqueElement {
+        OpaqueElement::new(self.node.value())
+    }
+
+    fn parent_element(&self) -> Option<Self> {
+        self.parent().and_then(ElementRef::wrap)
+    }
+
+    fn parent_node_is_shadow_root(&self) -> bool {
+        false
+    }
+
+    fn containing_shadow_host(&self) -> Option<Self> {
+        None
+    }
+
+    fn is_pseudo_element(&self) -> bool {
+        false
+    }
+
+    fn is_part(&self, _name: &CssLocalName) -> bool {
+        false
+    }
+
+    fn is_same_type(&self, other: &Self) -> bool {
+        self.value().name == other.value().name
+    }
+
+    fn imported_part(&self, _: &CssLocalName) -> Option<CssLocalName> {
+        None
+    }
+
+    fn prev_sibling_element(&self) -> Option<Self> {
+        self.prev_siblings()
+            .find(|sibling| sibling.value().is_element())
+            .map(ElementRef::new)
+    }
+
+    fn next_sibling_element(&self) -> Option<Self> {
+        self.next_siblings()
+            .find(|sibling| sibling.value().is_element())
+            .map(ElementRef::new)
+    }
+
+    fn first_element_child(&self) -> Option<Self> {
+        self.children()
+            .find(|child| child.value().is_element())
+            .map(ElementRef::new)
+    }
+
+    fn is_html_element_in_html_document(&self) -> bool {
+        // FIXME: Is there more to this?
+        self.value().name.ns == ns!(html)
+    }
+
+    fn has_local_name(&self, name: &CssLocalName) -> bool {
+        self.value().name.local == name.0
+    }
+
+    fn has_namespace(&self, namespace: &Namespace) -> bool {
+        &self.value().name.ns == namespace
+    }
+
+    fn attr_matches(
+        &self,
+        ns: &NamespaceConstraint<&Namespace>,
+        local_name: &CssLocalName,
+        operation: &AttrSelectorOperation<&CssString>,
+    ) -> bool {
+        self.value().attrs.iter().any(|(key, value)| {
+            !matches!(*ns, NamespaceConstraint::Specific(url) if *url != key.ns)
+                && local_name.0 == key.local
+                && operation.eval_str(value)
+        })
+    }
+
+    fn match_non_ts_pseudo_class(
+        &self,
+        _pc: &NonTSPseudoClass,
+        _context: &mut matching::MatchingContext<'_, Self::Impl>,
+    ) -> bool {
+        false
+    }
+
+    fn match_pseudo_element(
+        &self,
+        _pe: &PseudoElement,
+        _context: &mut matching::MatchingContext<Self::Impl>,
+    ) -> bool {
+        false
+    }
+
+    fn is_link(&self) -> bool {
+        self.value().name() == "link"
+    }
+
+    fn is_html_slot_element(&self) -> bool {
+        true
+    }
+
+    fn has_id(&self, id: &CssLocalName, case_sensitivity: CaseSensitivity) -> bool {
+        match self.value().id() {
+            Some(val) => case_sensitivity.eq(id.0.as_bytes(), val.as_bytes()),
+            None => false,
+        }
+    }
+
+    fn has_class(&self, name: &CssLocalName, case_sensitivity: CaseSensitivity) -> bool {
+        self.value().has_class(&name.0, case_sensitivity)
+    }
+
+    fn has_custom_state(&self, _name: &CssLocalName) -> bool {
+        false
+    }
+
+    fn is_empty(&self) -> bool {
+        !self
+            .children()
+            .any(|child| child.value().is_element() || child.value().is_text())
+    }
+
+    fn is_root(&self) -> bool {
+        self.parent()
+            .is_some_and(|parent| parent.value().is_document())
+    }
+
+    fn apply_selector_flags(&self, _flags: matching::ElementSelectorFlags) {}
+
+    fn add_element_unique_hashes(&self, _filter: &mut BloomFilter) -> bool {
+        // FIXME: Do we want to add `self.node.id()` here?
+        false
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::html::Html;
+    use crate::selector::{CssLocalName, Selector};
+    use selectors::attr::CaseSensitivity;
+    use selectors::Element;
+
+    #[test]
+    fn test_has_id() {
+        let html = "<p id='link_id_456'>hey there</p>";
+        let fragment = Html::parse_fragment(html);
+        let sel = Selector::parse("p").unwrap();
+
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(element.has_id(
+            &CssLocalName::from("link_id_456"),
+            CaseSensitivity::CaseSensitive
+        ));
+
+        let html = "<p>hey there</p>";
+        let fragment = Html::parse_fragment(html);
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(!element.has_id(
+            &CssLocalName::from("any_link_id"),
+            CaseSensitivity::CaseSensitive
+        ));
+    }
+
+    #[test]
+    fn test_is_link() {
+        let html = "<link href='https://www.example.com'>";
+        let fragment = Html::parse_fragment(html);
+        let sel = Selector::parse("link").unwrap();
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(element.is_link());
+
+        let html = "<p>hey there</p>";
+        let fragment = Html::parse_fragment(html);
+        let sel = Selector::parse("p").unwrap();
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(!element.is_link());
+    }
+
+    #[test]
+    fn test_has_class() {
+        let html = "<p class='my_class'>hey there</p>";
+        let fragment = Html::parse_fragment(html);
+        let sel = Selector::parse("p").unwrap();
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(element.has_class(
+            &CssLocalName::from("my_class"),
+            CaseSensitivity::CaseSensitive
+        ));
+
+        let html = "<p>hey there</p>";
+        let fragment = Html::parse_fragment(html);
+        let sel = Selector::parse("p").unwrap();
+        let element = fragment.select(&sel).next().unwrap();
+        assert!(!element.has_class(
+            &CssLocalName::from("my_class"),
+            CaseSensitivity::CaseSensitive
+        ));
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/mod.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/mod.rs
new file mode 100644
index 000000000000..cfe2a3d9c605
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/mod.rs
@@ -0,0 +1,236 @@
+//! Element references.
+
+use std::fmt::{self, Debug};
+use std::iter::FusedIterator;
+use std::ops::Deref;
+
+use ego_tree::iter::{Edge, Traverse};
+use ego_tree::NodeRef;
+use html5ever::serialize::{serialize, SerializeOpts, TraversalScope};
+use selectors::matching::SelectorCaches;
+
+use crate::node::Element;
+use crate::{Node, Selector};
+
+/// Wrapper around a reference to an element node.
+///
+/// This wrapper implements the `Element` trait from the `selectors` crate, which allows it to be
+/// matched against CSS selectors.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct ElementRef<'a> {
+    node: NodeRef<'a, Node>,
+}
+
+impl<'a> ElementRef<'a> {
+    fn new(node: NodeRef<'a, Node>) -> Self {
+        ElementRef { node }
+    }
+
+    /// Wraps a `NodeRef` only if it references a `Node::Element`.
+    pub fn wrap(node: NodeRef<'a, Node>) -> Option<Self> {
+        if node.value().is_element() {
+            Some(ElementRef::new(node))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the `Element` referenced by `self`.
+    pub fn value(&self) -> &'a Element {
+        self.node.value().as_element().unwrap()
+    }
+
+    /// Returns an iterator over descendent elements matching a selector.
+    pub fn select<'b>(&self, selector: &'b Selector) -> Select<'a, 'b> {
+        let mut inner = self.traverse();
+        inner.next(); // Skip Edge::Open(self).
+
+        Select {
+            scope: *self,
+            inner,
+            selector,
+            caches: Default::default(),
+        }
+    }
+
+    fn serialize(&self, traversal_scope: TraversalScope) -> String {
+        let opts = SerializeOpts {
+            scripting_enabled: false, // It's not clear what this does.
+            traversal_scope,
+            create_missing_parent: false,
+        };
+        let mut buf = Vec::new();
+        serialize(&mut buf, self, opts).unwrap();
+        String::from_utf8(buf).unwrap()
+    }
+
+    /// Returns the HTML of this element.
+    pub fn html(&self) -> String {
+        self.serialize(TraversalScope::IncludeNode)
+    }
+
+    /// Returns the inner HTML of this element.
+    pub fn inner_html(&self) -> String {
+        self.serialize(TraversalScope::ChildrenOnly(None))
+    }
+
+    /// Returns the value of an attribute.
+    pub fn attr(&self, attr: &str) -> Option<&'a str> {
+        self.value().attr(attr)
+    }
+
+    /// Returns an iterator over descendent text nodes.
+    pub fn text(&self) -> Text<'a> {
+        Text {
+            inner: self.traverse(),
+        }
+    }
+
+    /// Iterate over all child nodes which are elements
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use scraper::Html;
+    /// let fragment = Html::parse_fragment("foo<span>bar</span><a>baz</a>qux");
+    ///
+    /// let children = fragment.root_element().child_elements().map(|element| element.value().name()).collect::<Vec<_>>();
+    /// assert_eq!(children, ["span", "a"]);
+    /// ```
+    pub fn child_elements(&self) -> impl Iterator<Item = ElementRef<'a>> {
+        self.children().filter_map(ElementRef::wrap)
+    }
+
+    /// Iterate over all descendent nodes which are elements
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use scraper::Html;
+    /// let fragment = Html::parse_fragment("foo<span><b>bar</b></span><a><i>baz</i></a>qux");
+    ///
+    /// let descendants = fragment.root_element().descendent_elements().map(|element| element.value().name()).collect::<Vec<_>>();
+    /// assert_eq!(descendants, ["html", "span", "b", "a", "i"]);
+    /// ```
+    pub fn descendent_elements(&self) -> impl Iterator<Item = ElementRef<'a>> {
+        self.descendants().filter_map(ElementRef::wrap)
+    }
+}
+
+impl Debug for ElementRef<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        Debug::fmt(self.value(), f)
+    }
+}
+
+impl<'a> Deref for ElementRef<'a> {
+    type Target = NodeRef<'a, Node>;
+    fn deref(&self) -> &NodeRef<'a, Node> {
+        &self.node
+    }
+}
+
+/// Iterator over descendent elements matching a selector.
+pub struct Select<'a, 'b> {
+    scope: ElementRef<'a>,
+    inner: Traverse<'a, Node>,
+    selector: &'b Selector,
+    caches: SelectorCaches,
+}
+
+impl Debug for Select<'_, '_> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt.debug_struct("Select")
+            .field("scope", &self.scope)
+            .field("inner", &self.inner)
+            .field("selector", &self.selector)
+            .field("caches", &"..")
+            .finish()
+    }
+}
+
+impl Clone for Select<'_, '_> {
+    fn clone(&self) -> Self {
+        Self {
+            scope: self.scope,
+            inner: self.inner.clone(),
+            selector: self.selector,
+            caches: Default::default(),
+        }
+    }
+}
+
+impl<'a> Iterator for Select<'a, '_> {
+    type Item = ElementRef<'a>;
+
+    fn next(&mut self) -> Option<ElementRef<'a>> {
+        for edge in &mut self.inner {
+            if let Edge::Open(node) = edge {
+                if let Some(element) = ElementRef::wrap(node) {
+                    if self.selector.matches_with_scope_and_cache(
+                        &element,
+                        Some(self.scope),
+                        &mut self.caches,
+                    ) {
+                        return Some(element);
+                    }
+                }
+            }
+        }
+        None
+    }
+}
+
+impl FusedIterator for Select<'_, '_> {}
+
+/// Iterator over descendent text nodes.
+#[derive(Debug, Clone)]
+pub struct Text<'a> {
+    inner: Traverse<'a, Node>,
+}
+
+impl<'a> Iterator for Text<'a> {
+    type Item = &'a str;
+
+    fn next(&mut self) -> Option<&'a str> {
+        for edge in &mut self.inner {
+            if let Edge::Open(node) = edge {
+                if let Node::Text(ref text) = node.value() {
+                    return Some(&**text);
+                }
+            }
+        }
+        None
+    }
+}
+
+impl FusedIterator for Text<'_> {}
+
+mod element;
+mod serializable;
+
+#[cfg(test)]
+mod tests {
+    use crate::html::Html;
+    use crate::selector::Selector;
+
+    #[test]
+    fn test_scope() {
+        let html = r"
+            <div>
+                <b>1</b>
+                <span>
+                    <span><b>2</b></span>
+                    <b>3</b>
+                </span>
+            </div>
+        ";
+        let fragment = Html::parse_fragment(html);
+        let sel1 = Selector::parse("div > span").unwrap();
+        let sel2 = Selector::parse(":scope > b").unwrap();
+
+        let element1 = fragment.select(&sel1).next().unwrap();
+        let element2 = element1.select(&sel2).next().unwrap();
+        assert_eq!(element2.inner_html(), "3");
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/serializable.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/serializable.rs
new file mode 100644
index 000000000000..0b88c8d32e8f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/serializable.rs
@@ -0,0 +1,15 @@
+use std::io::Error;
+
+use html5ever::serialize::{Serialize, Serializer, TraversalScope};
+
+use crate::ElementRef;
+
+impl Serialize for ElementRef<'_> {
+    fn serialize<S: Serializer>(
+        &self,
+        serializer: &mut S,
+        traversal_scope: TraversalScope,
+    ) -> Result<(), Error> {
+        crate::node::serializable::serialize(**self, serializer, traversal_scope)
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error.rs
new file mode 100644
index 000000000000..ef27dea14754
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error.rs
@@ -0,0 +1,119 @@
+//! Custom error types for diagnostics
+//! Includes re-exported error types from dependencies
+
+mod utils;
+
+use std::{error::Error, fmt::Display};
+
+use cssparser::{BasicParseErrorKind, ParseErrorKind, Token};
+use selectors::parser::SelectorParseErrorKind;
+
+/// Error type that is returned when calling `Selector::parse`
+#[derive(Debug, Clone)]
+pub enum SelectorErrorKind<'a> {
+    /// A `Token` was not expected
+    UnexpectedToken(Token<'a>),
+
+    /// End-Of-Line was unexpected
+    EndOfLine,
+
+    /// `@` rule is invalid
+    InvalidAtRule(String),
+
+    /// The body of an `@` rule is invalid
+    InvalidAtRuleBody,
+
+    /// The qualified rule is invalid
+    QualRuleInvalid,
+
+    /// Expected a `::` for a pseudoelement
+    ExpectedColonOnPseudoElement(Token<'a>),
+
+    /// Expected an identity for a pseudoelement
+    ExpectedIdentityOnPseudoElement(Token<'a>),
+
+    /// A `SelectorParseErrorKind` error that isn't really supposed to happen did
+    UnexpectedSelectorParseError(SelectorParseErrorKind<'a>),
+}
+
+impl<'a> From<cssparser::ParseError<'a, SelectorParseErrorKind<'a>>> for SelectorErrorKind<'a> {
+    fn from(original: cssparser::ParseError<'a, SelectorParseErrorKind<'a>>) -> Self {
+        // NOTE: This could be improved, but I dont
+        // exactly know how
+        match original.kind {
+            ParseErrorKind::Basic(err) => SelectorErrorKind::from(err),
+            ParseErrorKind::Custom(err) => SelectorErrorKind::from(err),
+        }
+    }
+}
+
+impl<'a> From<BasicParseErrorKind<'a>> for SelectorErrorKind<'a> {
+    fn from(err: BasicParseErrorKind<'a>) -> Self {
+        match err {
+            BasicParseErrorKind::UnexpectedToken(token) => Self::UnexpectedToken(token),
+            BasicParseErrorKind::EndOfInput => Self::EndOfLine,
+            BasicParseErrorKind::AtRuleInvalid(rule) => Self::InvalidAtRule(rule.to_string()),
+            BasicParseErrorKind::AtRuleBodyInvalid => Self::InvalidAtRuleBody,
+            BasicParseErrorKind::QualifiedRuleInvalid => Self::QualRuleInvalid,
+        }
+    }
+}
+
+impl<'a> From<SelectorParseErrorKind<'a>> for SelectorErrorKind<'a> {
+    fn from(err: SelectorParseErrorKind<'a>) -> Self {
+        match err {
+            SelectorParseErrorKind::PseudoElementExpectedColon(token) => {
+                Self::ExpectedColonOnPseudoElement(token)
+            }
+            SelectorParseErrorKind::PseudoElementExpectedIdent(token) => {
+                Self::ExpectedIdentityOnPseudoElement(token)
+            }
+            other => Self::UnexpectedSelectorParseError(other),
+        }
+    }
+}
+
+impl Display for SelectorErrorKind<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                Self::UnexpectedToken(token) => {
+                    format!("Token {:?} was not expected", utils::render_token(token))
+                }
+                Self::EndOfLine => "Unexpected EOL".to_string(),
+                Self::InvalidAtRule(rule) => format!("Invalid @-rule {:?}", rule),
+                Self::InvalidAtRuleBody => "The body of an @-rule was invalid".to_string(),
+                Self::QualRuleInvalid => "The qualified name was invalid".to_string(),
+                Self::ExpectedColonOnPseudoElement(token) => format!(
+                    "Expected a ':' token for pseudoelement, got {:?} instead",
+                    utils::render_token(token)
+                ),
+                Self::ExpectedIdentityOnPseudoElement(token) => format!(
+                    "Expected identity for pseudoelement, got {:?} instead",
+                    utils::render_token(token)
+                ),
+                Self::UnexpectedSelectorParseError(err) => format!(
+                    "Unexpected error occurred. Please report this to the developer\n{:#?}",
+                    err
+                ),
+            }
+        )
+    }
+}
+
+impl Error for SelectorErrorKind<'_> {
+    fn description(&self) -> &str {
+        match self {
+            Self::UnexpectedToken(_) => "Token was not expected",
+            Self::EndOfLine => "Unexpected EOL",
+            Self::InvalidAtRule(_) => "Invalid @-rule",
+            Self::InvalidAtRuleBody => "The body of an @-rule was invalid",
+            Self::QualRuleInvalid => "The qualified name was invalid",
+            Self::ExpectedColonOnPseudoElement(_) => "Missing colon character on pseudoelement",
+            Self::ExpectedIdentityOnPseudoElement(_) => "Missing pseudoelement identity",
+            Self::UnexpectedSelectorParseError(_) => "Unexpected error",
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error/utils.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error/utils.rs
new file mode 100644
index 000000000000..39a4013fcc96
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error/utils.rs
@@ -0,0 +1,91 @@
+use cssparser::Token;
+
+pub(crate) fn render_token(token: &Token<'_>) -> String {
+    match token {
+        Token::Ident(ident) => ident.to_string(),
+        Token::AtKeyword(value) => format!("@{}", value),
+        Token::Hash(name) | Token::IDHash(name) => format!("#{}", name),
+        Token::QuotedString(value) => format!("\"{}\"", value),
+        Token::UnquotedUrl(value) => value.to_string(),
+        Token::Number {
+            has_sign: signed,
+            value: num,
+            int_value: _,
+        }
+        | Token::Percentage {
+            has_sign: signed,
+            unit_value: num,
+            int_value: _,
+        } => render_number(*signed, *num, token),
+        Token::Dimension {
+            has_sign: signed,
+            value: num,
+            int_value: _,
+            unit,
+        } => format!("{}{}", render_int(*signed, *num), unit),
+        Token::WhiteSpace(_) => String::from(" "),
+        Token::Comment(comment) => format!("/* {} */", comment),
+        Token::Function(name) => format!("{}()", name),
+        Token::BadString(string) => format!("<Bad String {:?}>", string),
+        Token::BadUrl(url) => format!("<Bad URL {:?}>", url),
+        // Single-character token
+        Token::Colon => ":".into(),
+        Token::Semicolon => ";".into(),
+        Token::Comma => ",".into(),
+        Token::IncludeMatch => "~=".into(),
+        Token::DashMatch => "|=".into(),
+        Token::PrefixMatch => "^=".into(),
+        Token::SuffixMatch => "$=".into(),
+        Token::SubstringMatch => "*=".into(),
+        Token::CDO => "<!--".into(),
+        Token::CDC => "-->".into(),
+        Token::ParenthesisBlock => "<(".into(),
+        Token::SquareBracketBlock => "<[".into(),
+        Token::CurlyBracketBlock => "<{".into(),
+        Token::CloseParenthesis => "<)".into(),
+        Token::CloseSquareBracket => "<]".into(),
+        Token::CloseCurlyBracket => "<}".into(),
+        Token::Delim(delim) => (*delim).into(),
+    }
+}
+
+fn render_number(signed: bool, num: f32, token: &Token) -> String {
+    let num = render_int(signed, num);
+
+    match token {
+        Token::Number { .. } => num,
+        Token::Percentage { .. } => format!("{}%", num),
+        _ => panic!("render_number is not supposed to be called on a non-numerical token"),
+    }
+}
+
+fn render_int(signed: bool, num: f32) -> String {
+    if signed {
+        render_int_signed(num)
+    } else {
+        render_int_unsigned(num)
+    }
+}
+
+fn render_int_signed(num: f32) -> String {
+    if num > 0.0 {
+        format!("+{}", num)
+    } else {
+        format!("-{}", num)
+    }
+}
+
+fn render_int_unsigned(num: f32) -> String {
+    format!("{}", num)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::Selector;
+
+    #[test]
+    fn regression_test_issue212() {
+        let err = Selector::parse("div138293@!#@!!@#").unwrap_err();
+        assert_eq!(err.to_string(), "Token \"@\" was not expected");
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/mod.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/mod.rs
new file mode 100644
index 000000000000..f64578bbe11a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/mod.rs
@@ -0,0 +1,269 @@
+//! HTML documents and fragments.
+
+#[cfg(feature = "errors")]
+use std::borrow::Cow;
+use std::fmt;
+use std::iter::FusedIterator;
+
+use ego_tree::iter::Nodes;
+use ego_tree::Tree;
+use html5ever::serialize::SerializeOpts;
+use html5ever::tree_builder::QuirksMode;
+use html5ever::{driver, serialize, QualName};
+use selectors::matching::SelectorCaches;
+use tendril::TendrilSink;
+
+use crate::selector::Selector;
+use crate::{ElementRef, Node};
+
+pub use tree_sink::HtmlTreeSink;
+
+/// An HTML tree.
+///
+/// Parsing does not fail hard. Instead, the `quirks_mode` is set and errors are added to the
+/// `errors` field. The `tree` will still be populated as best as possible.
+///
+/// Implements the `TreeSink` trait from the `html5ever` crate, which allows HTML to be parsed.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Html {
+    #[cfg(feature = "errors")]
+    /// Parse errors.
+    pub errors: Vec<Cow<'static, str>>,
+
+    /// The quirks mode.
+    pub quirks_mode: QuirksMode,
+
+    /// The node tree.
+    pub tree: Tree<Node>,
+}
+
+impl Html {
+    /// Creates an empty HTML document.
+    pub fn new_document() -> Self {
+        Html {
+            #[cfg(feature = "errors")]
+            errors: Vec::new(),
+            quirks_mode: QuirksMode::NoQuirks,
+            tree: Tree::new(Node::Document),
+        }
+    }
+
+    /// Creates an empty HTML fragment.
+    pub fn new_fragment() -> Self {
+        Html {
+            #[cfg(feature = "errors")]
+            errors: Vec::new(),
+            quirks_mode: QuirksMode::NoQuirks,
+            tree: Tree::new(Node::Fragment),
+        }
+    }
+
+    /// Parses a string of HTML as a document.
+    ///
+    /// This is a convenience method for the following:
+    ///
+    /// ```
+    /// # extern crate html5ever;
+    /// # extern crate scraper;
+    /// # extern crate tendril;
+    /// # fn main() {
+    /// # let document = "";
+    /// use html5ever::driver::{self, ParseOpts};
+    /// use scraper::{Html, HtmlTreeSink};
+    /// use tendril::TendrilSink;
+    ///
+    /// let parser = driver::parse_document(HtmlTreeSink::new(Html::new_document()), ParseOpts::default());
+    /// let html = parser.one(document);
+    /// # }
+    /// ```
+    pub fn parse_document(document: &str) -> Self {
+        let parser =
+            driver::parse_document(HtmlTreeSink::new(Self::new_document()), Default::default());
+        parser.one(document)
+    }
+
+    /// Parses a string of HTML as a fragment.
+    pub fn parse_fragment(fragment: &str) -> Self {
+        let parser = driver::parse_fragment(
+            HtmlTreeSink::new(Self::new_fragment()),
+            Default::default(),
+            QualName::new(None, ns!(html), local_name!("body")),
+            Vec::new(),
+        );
+        parser.one(fragment)
+    }
+
+    /// Returns an iterator over elements matching a selector.
+    pub fn select<'a, 'b>(&'a self, selector: &'b Selector) -> Select<'a, 'b> {
+        Select {
+            inner: self.tree.nodes(),
+            selector,
+            caches: Default::default(),
+        }
+    }
+
+    /// Returns the root `<html>` element.
+    pub fn root_element(&self) -> ElementRef {
+        let root_node = self
+            .tree
+            .root()
+            .children()
+            .find(|child| child.value().is_element())
+            .expect("html node missing");
+        ElementRef::wrap(root_node).unwrap()
+    }
+
+    /// Serialize entire document into HTML.
+    pub fn html(&self) -> String {
+        let opts = SerializeOpts {
+            scripting_enabled: false, // It's not clear what this does.
+            traversal_scope: serialize::TraversalScope::IncludeNode,
+            create_missing_parent: false,
+        };
+        let mut buf = Vec::new();
+        serialize(&mut buf, self, opts).unwrap();
+        String::from_utf8(buf).unwrap()
+    }
+}
+
+/// Iterator over elements matching a selector.
+pub struct Select<'a, 'b> {
+    inner: Nodes<'a, Node>,
+    selector: &'b Selector,
+    caches: SelectorCaches,
+}
+
+impl fmt::Debug for Select<'_, '_> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt.debug_struct("Select")
+            .field("inner", &self.inner)
+            .field("selector", &self.selector)
+            .field("caches", &"..")
+            .finish()
+    }
+}
+
+impl Clone for Select<'_, '_> {
+    fn clone(&self) -> Self {
+        Self {
+            inner: self.inner.clone(),
+            selector: self.selector,
+            caches: Default::default(),
+        }
+    }
+}
+
+impl<'a> Iterator for Select<'a, '_> {
+    type Item = ElementRef<'a>;
+
+    fn next(&mut self) -> Option<ElementRef<'a>> {
+        for node in self.inner.by_ref() {
+            if let Some(element) = ElementRef::wrap(node) {
+                if element.parent().is_some()
+                    && self
+                        .selector
+                        .matches_with_scope_and_cache(&element, None, &mut self.caches)
+                {
+                    return Some(element);
+                }
+            }
+        }
+        None
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (_lower, upper) = self.inner.size_hint();
+
+        (0, upper)
+    }
+}
+
+impl DoubleEndedIterator for Select<'_, '_> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        for node in self.inner.by_ref().rev() {
+            if let Some(element) = ElementRef::wrap(node) {
+                if element.parent().is_some()
+                    && self
+                        .selector
+                        .matches_with_scope_and_cache(&element, None, &mut self.caches)
+                {
+                    return Some(element);
+                }
+            }
+        }
+        None
+    }
+}
+
+impl FusedIterator for Select<'_, '_> {}
+
+mod serializable;
+mod tree_sink;
+
+#[cfg(test)]
+mod tests {
+    use super::Html;
+    use super::Selector;
+
+    #[test]
+    fn root_element_fragment() {
+        let html = Html::parse_fragment(r#"<a href="http://github.com">1</a>"#);
+        let root_ref = html.root_element();
+        let href = root_ref
+            .select(&Selector::parse("a").unwrap())
+            .next()
+            .unwrap();
+        assert_eq!(href.inner_html(), "1");
+        assert_eq!(href.value().attr("href").unwrap(), "http://github.com");
+    }
+
+    #[test]
+    fn root_element_document_doctype() {
+        let html = Html::parse_document("<!DOCTYPE html>\n<title>abc</title>");
+        let root_ref = html.root_element();
+        let title = root_ref
+            .select(&Selector::parse("title").unwrap())
+            .next()
+            .unwrap();
+        assert_eq!(title.inner_html(), "abc");
+    }
+
+    #[test]
+    fn root_element_document_comment() {
+        let html = Html::parse_document("<!-- comment --><title>abc</title>");
+        let root_ref = html.root_element();
+        let title = root_ref
+            .select(&Selector::parse("title").unwrap())
+            .next()
+            .unwrap();
+        assert_eq!(title.inner_html(), "abc");
+    }
+
+    #[test]
+    fn select_is_reversible() {
+        let html = Html::parse_document("<p>element1</p><p>element2</p><p>element3</p>");
+        let selector = Selector::parse("p").unwrap();
+        let result: Vec<_> = html
+            .select(&selector)
+            .rev()
+            .map(|e| e.inner_html())
+            .collect();
+        assert_eq!(result, vec!["element3", "element2", "element1"]);
+    }
+
+    #[test]
+    fn select_has_a_size_hint() {
+        let html = Html::parse_document("<p>element1</p><p>element2</p><p>element3</p>");
+        let selector = Selector::parse("p").unwrap();
+        let (lower, upper) = html.select(&selector).size_hint();
+        assert_eq!(lower, 0);
+        assert_eq!(upper, Some(10));
+    }
+
+    #[cfg(feature = "atomic")]
+    #[test]
+    fn html_is_send() {
+        fn send_sync<S: Send>() {}
+        send_sync::<Html>();
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/serializable.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/serializable.rs
new file mode 100644
index 000000000000..a30a2ccd1ea3
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/serializable.rs
@@ -0,0 +1,27 @@
+use std::io::Error;
+
+use html5ever::serialize::{Serialize, Serializer, TraversalScope};
+
+use crate::Html;
+
+impl Serialize for Html {
+    fn serialize<S: Serializer>(
+        &self,
+        serializer: &mut S,
+        traversal_scope: TraversalScope,
+    ) -> Result<(), Error> {
+        crate::node::serializable::serialize(self.tree.root(), serializer, traversal_scope)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::Html;
+
+    #[test]
+    fn test_serialize() {
+        let src = r#"<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"></head><body><p>Hello world!</p></body></html>"#;
+        let html = Html::parse_document(src);
+        assert_eq!(html.html(), src);
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/tree_sink.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/tree_sink.rs
new file mode 100644
index 000000000000..49b30b495527
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/tree_sink.rs
@@ -0,0 +1,297 @@
+use super::Html;
+use crate::node::{Comment, Doctype, Element, Node, ProcessingInstruction, Text};
+use crate::tendril_util::make as make_tendril;
+use ego_tree::NodeId;
+use html5ever::tendril::StrTendril;
+use html5ever::tree_builder::{ElementFlags, NodeOrText, QuirksMode, TreeSink};
+use html5ever::Attribute;
+use html5ever::QualName;
+use std::borrow::Cow;
+use std::cell::{Ref, RefCell};
+
+/// Wraps `Html` instances as sinks to drive parsing
+#[derive(Debug)]
+pub struct HtmlTreeSink(RefCell<Html>);
+
+impl HtmlTreeSink {
+    /// Wrap a `Html`instance as a sink to drive parsing
+    pub fn new(html: Html) -> Self {
+        Self(RefCell::new(html))
+    }
+}
+
+/// Note: does not support the `<template>` element.
+impl TreeSink for HtmlTreeSink {
+    type Output = Html;
+    type Handle = NodeId;
+    type ElemName<'a> = Ref<'a, QualName>;
+
+    fn finish(self) -> Html {
+        self.0.into_inner()
+    }
+
+    // Signal a parse error.
+    fn parse_error(&self, msg: Cow<'static, str>) {
+        #[cfg(feature = "errors")]
+        self.0.borrow_mut().errors.push(msg);
+        #[cfg(not(feature = "errors"))]
+        let _ = msg;
+    }
+
+    // Set the document's quirks mode.
+    fn set_quirks_mode(&self, mode: QuirksMode) {
+        self.0.borrow_mut().quirks_mode = mode;
+    }
+
+    // Get a handle to the Document node.
+    fn get_document(&self) -> Self::Handle {
+        self.0.borrow().tree.root().id()
+    }
+
+    // Do two handles refer to the same node?
+    fn same_node(&self, x: &Self::Handle, y: &Self::Handle) -> bool {
+        x == y
+    }
+
+    // What is the name of this element?
+    //
+    // Should never be called on a non-element node; feel free to panic!.
+    fn elem_name<'a>(&'a self, target: &Self::Handle) -> Ref<'a, QualName> {
+        Ref::map(self.0.borrow(), |this| {
+            &this
+                .tree
+                .get(*target)
+                .unwrap()
+                .value()
+                .as_element()
+                .unwrap()
+                .name
+        })
+    }
+
+    // Create an element.
+    //
+    // When creating a template element (name.expanded() == expanded_name!(html "template")), an
+    // associated document fragment called the "template contents" should also be created. Later
+    // calls to self.get_template_contents() with that given element return it.
+    fn create_element(
+        &self,
+        name: QualName,
+        attrs: Vec<Attribute>,
+        _flags: ElementFlags,
+    ) -> Self::Handle {
+        let fragment = name.expanded() == expanded_name!(html "template");
+
+        let mut this = self.0.borrow_mut();
+        let mut node = this.tree.orphan(Node::Element(Element::new(name, attrs)));
+
+        if fragment {
+            node.append(Node::Fragment);
+        }
+
+        node.id()
+    }
+
+    // Create a comment node.
+    fn create_comment(&self, text: StrTendril) -> Self::Handle {
+        self.0
+            .borrow_mut()
+            .tree
+            .orphan(Node::Comment(Comment {
+                comment: make_tendril(text),
+            }))
+            .id()
+    }
+
+    // Append a DOCTYPE element to the Document node.
+    fn append_doctype_to_document(
+        &self,
+        name: StrTendril,
+        public_id: StrTendril,
+        system_id: StrTendril,
+    ) {
+        let name = make_tendril(name);
+        let public_id = make_tendril(public_id);
+        let system_id = make_tendril(system_id);
+        let doctype = Doctype {
+            name,
+            public_id,
+            system_id,
+        };
+        self.0
+            .borrow_mut()
+            .tree
+            .root_mut()
+            .append(Node::Doctype(doctype));
+    }
+
+    // Append a node as the last child of the given node. If this would produce adjacent sibling
+    // text nodes, it should concatenate the text instead.
+    //
+    // The child node will not already have a parent.
+    fn append(&self, parent: &Self::Handle, child: NodeOrText<Self::Handle>) {
+        let mut this = self.0.borrow_mut();
+        let mut parent = this.tree.get_mut(*parent).unwrap();
+
+        match child {
+            NodeOrText::AppendNode(id) => {
+                parent.append_id(id);
+            }
+
+            NodeOrText::AppendText(text) => {
+                let text = make_tendril(text);
+
+                let did_concat = parent.last_child().is_some_and(|mut n| match n.value() {
+                    Node::Text(t) => {
+                        t.text.push_tendril(&text);
+                        true
+                    }
+                    _ => false,
+                });
+
+                if !did_concat {
+                    parent.append(Node::Text(Text { text }));
+                }
+            }
+        }
+    }
+
+    // Append a node as the sibling immediately before the given node. If that node has no parent,
+    // do nothing and return Err(new_node).
+    //
+    // The tree builder promises that sibling is not a text node. However its old previous sibling,
+    // which would become the new node's previous sibling, could be a text node. If the new node is
+    // also a text node, the two should be merged, as in the behavior of append.
+    //
+    // NB: new_node may have an old parent, from which it should be removed.
+    fn append_before_sibling(&self, sibling: &Self::Handle, new_node: NodeOrText<Self::Handle>) {
+        let mut this = self.0.borrow_mut();
+
+        if let NodeOrText::AppendNode(id) = new_node {
+            this.tree.get_mut(id).unwrap().detach();
+        }
+
+        let mut sibling = this.tree.get_mut(*sibling).unwrap();
+        if sibling.parent().is_some() {
+            match new_node {
+                NodeOrText::AppendNode(id) => {
+                    sibling.insert_id_before(id);
+                }
+
+                NodeOrText::AppendText(text) => {
+                    let text = make_tendril(text);
+
+                    let did_concat = sibling.prev_sibling().is_some_and(|mut n| match n.value() {
+                        Node::Text(t) => {
+                            t.text.push_tendril(&text);
+                            true
+                        }
+                        _ => false,
+                    });
+
+                    if !did_concat {
+                        sibling.insert_before(Node::Text(Text { text }));
+                    }
+                }
+            }
+        }
+    }
+
+    // Detach the given node from its parent.
+    fn remove_from_parent(&self, target: &Self::Handle) {
+        self.0.borrow_mut().tree.get_mut(*target).unwrap().detach();
+    }
+
+    // Remove all the children from node and append them to new_parent.
+    fn reparent_children(&self, node: &Self::Handle, new_parent: &Self::Handle) {
+        self.0
+            .borrow_mut()
+            .tree
+            .get_mut(*new_parent)
+            .unwrap()
+            .reparent_from_id_append(*node);
+    }
+
+    // Add each attribute to the given element, if no attribute with that name already exists. The
+    // tree builder promises this will never be called with something else than an element.
+    fn add_attrs_if_missing(&self, target: &Self::Handle, attrs: Vec<Attribute>) {
+        let mut this = self.0.borrow_mut();
+        let mut node = this.tree.get_mut(*target).unwrap();
+        let element = match *node.value() {
+            Node::Element(ref mut e) => e,
+            _ => unreachable!(),
+        };
+
+        for attr in attrs {
+            #[cfg(not(feature = "deterministic"))]
+            if let Err(idx) = element
+                .attrs
+                .binary_search_by(|(name, _)| name.cmp(&attr.name))
+            {
+                element
+                    .attrs
+                    .insert(idx, (attr.name, make_tendril(attr.value)));
+            }
+
+            #[cfg(feature = "deterministic")]
+            element
+                .attrs
+                .entry(attr.name)
+                .or_insert_with(|| make_tendril(attr.value));
+        }
+    }
+
+    // Get a handle to a template's template contents.
+    //
+    // The tree builder promises this will never be called with something else than a template
+    // element.
+    fn get_template_contents(&self, target: &Self::Handle) -> Self::Handle {
+        self.0
+            .borrow()
+            .tree
+            .get(*target)
+            .unwrap()
+            .first_child()
+            .unwrap()
+            .id()
+    }
+
+    // Mark a HTML <script> element as "already started".
+    fn mark_script_already_started(&self, _node: &Self::Handle) {}
+
+    // Create Processing Instruction.
+    fn create_pi(&self, target: StrTendril, data: StrTendril) -> Self::Handle {
+        let target = make_tendril(target);
+        let data = make_tendril(data);
+        self.0
+            .borrow_mut()
+            .tree
+            .orphan(Node::ProcessingInstruction(ProcessingInstruction {
+                target,
+                data,
+            }))
+            .id()
+    }
+
+    fn append_based_on_parent_node(
+        &self,
+        element: &Self::Handle,
+        prev_element: &Self::Handle,
+        child: NodeOrText<Self::Handle>,
+    ) {
+        let has_parent = self
+            .0
+            .borrow()
+            .tree
+            .get(*element)
+            .unwrap()
+            .parent()
+            .is_some();
+
+        if has_parent {
+            self.append_before_sibling(element, child)
+        } else {
+            self.append(prev_element, child)
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs
new file mode 100644
index 000000000000..46ca06475991
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs
@@ -0,0 +1,182 @@
+//! HTML parsing and querying with CSS selectors.
+//!
+//! `scraper` is on [Crates.io][crate] and [GitHub][github].
+//!
+//! [crate]: https://crates.io/crates/scraper
+//! [github]: https://github.com/programble/scraper
+//!
+//! Scraper provides an interface to Servo's `html5ever` and `selectors` crates, for browser-grade
+//! parsing and querying.
+//!
+//! # Examples
+//!
+//! ## Parsing a document
+//!
+//! ```
+//! use scraper::Html;
+//!
+//! let html = r#"
+//!     <!DOCTYPE html>
+//!     <meta charset="utf-8">
+//!     <title>Hello, world!</title>
+//!     <h1 class="foo">Hello, <i>world!</i></h1>
+//! "#;
+//!
+//! let document = Html::parse_document(html);
+//! ```
+//!
+//! ## Parsing a fragment
+//!
+//! ```
+//! use scraper::Html;
+//! let fragment = Html::parse_fragment("<h1>Hello, <i>world!</i></h1>");
+//! ```
+//!
+//! ## Parsing a selector
+//!
+//! ```
+//! use scraper::Selector;
+//! let selector = Selector::parse("h1.foo").unwrap();
+//! ```
+//!
+//! ## Selecting elements
+//!
+//! ```
+//! use scraper::{Html, Selector};
+//!
+//! let html = r#"
+//!     <ul>
+//!         <li>Foo</li>
+//!         <li>Bar</li>
+//!         <li>Baz</li>
+//!     </ul>
+//! "#;
+//!
+//! let fragment = Html::parse_fragment(html);
+//! let selector = Selector::parse("li").unwrap();
+//!
+//! for element in fragment.select(&selector) {
+//!     assert_eq!("li", element.value().name());
+//! }
+//! ```
+//!
+//! ## Selecting descendent elements
+//!
+//! ```
+//! use scraper::{Html, Selector};
+//!
+//! let html = r#"
+//!     <ul>
+//!         <li>Foo</li>
+//!         <li>Bar</li>
+//!         <li>Baz</li>
+//!     </ul>
+//! "#;
+//!
+//! let fragment = Html::parse_fragment(html);
+//! let ul_selector = Selector::parse("ul").unwrap();
+//! let li_selector = Selector::parse("li").unwrap();
+//!
+//! let ul = fragment.select(&ul_selector).next().unwrap();
+//! for element in ul.select(&li_selector) {
+//!     assert_eq!("li", element.value().name());
+//! }
+//! ```
+//!
+//! ## Accessing element attributes
+//!
+//! ```
+//! use scraper::{Html, Selector};
+//!
+//! let fragment = Html::parse_fragment(r#"<input name="foo" value="bar">"#);
+//! let selector = Selector::parse(r#"input[name="foo"]"#).unwrap();
+//!
+//! let input = fragment.select(&selector).next().unwrap();
+//! assert_eq!(Some("bar"), input.value().attr("value"));
+//! ```
+//!
+//! ## Serializing HTML and inner HTML
+//!
+//! ```
+//! use scraper::{Html, Selector};
+//!
+//! let fragment = Html::parse_fragment("<h1>Hello, <i>world!</i></h1>");
+//! let selector = Selector::parse("h1").unwrap();
+//!
+//! let h1 = fragment.select(&selector).next().unwrap();
+//!
+//! assert_eq!("<h1>Hello, <i>world!</i></h1>", h1.html());
+//! assert_eq!("Hello, <i>world!</i>", h1.inner_html());
+//! ```
+//!
+//! ## Accessing descendent text
+//!
+//! ```
+//! use scraper::{Html, Selector};
+//!
+//! let fragment = Html::parse_fragment("<h1>Hello, <i>world!</i></h1>");
+//! let selector = Selector::parse("h1").unwrap();
+//!
+//! let h1 = fragment.select(&selector).next().unwrap();
+//! let text = h1.text().collect::<Vec<_>>();
+//!
+//! assert_eq!(vec!["Hello, ", "world!"], text);
+//! ```
+
+#![warn(
+    missing_docs,
+    missing_debug_implementations,
+    missing_copy_implementations,
+    trivial_casts,
+    trivial_numeric_casts,
+    unused_extern_crates,
+    unused_import_braces,
+    unused_qualifications,
+    variant_size_differences
+)]
+
+#[macro_use]
+extern crate html5ever;
+
+pub use crate::element_ref::ElementRef;
+pub use crate::html::{Html, HtmlTreeSink};
+pub use crate::node::Node;
+pub use crate::selector::Selector;
+
+pub use selectors::{attr::CaseSensitivity, Element};
+
+pub mod element_ref;
+pub mod error;
+pub mod html;
+pub mod node;
+pub mod selectable;
+pub mod selector;
+
+#[cfg(feature = "atomic")]
+pub(crate) mod tendril_util {
+    use html5ever::tendril;
+    /// Atomic equivalent to the default `StrTendril` type.
+    pub type StrTendril = tendril::Tendril<tendril::fmt::UTF8, tendril::Atomic>;
+
+    /// Convert a standard tendril into an atomic one.
+    pub fn make(s: tendril::StrTendril) -> StrTendril {
+        s.into_send().into()
+    }
+}
+
+#[cfg(not(feature = "atomic"))]
+pub(crate) mod tendril_util {
+    use html5ever::tendril;
+    /// Primary string tendril type.
+    pub type StrTendril = tendril::StrTendril;
+
+    /// Return unaltered.
+    pub fn make(s: StrTendril) -> StrTendril {
+        s
+    }
+}
+
+pub use tendril_util::StrTendril;
+
+#[cfg(test)]
+mod test;
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/main.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/main.rs
new file mode 100644
index 000000000000..8f9de9fab85d
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/main.rs
@@ -0,0 +1,132 @@
+extern crate getopts;
+extern crate scraper;
+
+use getopts::Options;
+use scraper::{Html, Selector};
+use std::env;
+use std::fs::{self, File};
+use std::io::{self, Read};
+use std::path::PathBuf;
+use std::process;
+
+enum Input {
+    Document,
+    Fragment,
+}
+
+enum Output {
+    Html,
+    InnerHtml,
+    Attr(String),
+    Classes,
+    Id,
+    Name,
+    Text,
+}
+
+fn query<T: Read>(input: &Input, output: &Output, selector: &Selector, file: &mut T) -> bool {
+    let mut html = String::new();
+    file.read_to_string(&mut html).unwrap();
+
+    let html = match *input {
+        Input::Document => Html::parse_document(&html),
+        Input::Fragment => Html::parse_fragment(&html),
+    };
+
+    let mut matched = false;
+    for element in html.select(selector) {
+        use crate::Output::*;
+        match *output {
+            Html => println!("{}", element.html()),
+            InnerHtml => println!("{}", element.inner_html()),
+            Attr(ref attr) => println!("{}", element.value().attr(attr).unwrap_or("")),
+            Classes => println!(
+                "{}",
+                element.value().classes().collect::<Vec<_>>().join(" ")
+            ),
+            Id => println!("{}", element.value().id().unwrap_or("")),
+            Name => println!("{}", element.value().name()),
+            Text => println!("{}", element.text().collect::<String>()),
+        }
+        matched = true;
+    }
+    matched
+}
+
+fn main() {
+    let mut opts = Options::new();
+    opts.optflag("H", "html", "output HTML of elements");
+    opts.optflag("I", "inner-html", "output inner HTML of elements");
+    opts.optopt("a", "attr", "output attribute value of elements", "ATTR");
+    opts.optflag("c", "classes", "output classes of elements");
+    opts.optflag("d", "document", "parse input as HTML documents");
+    opts.optflag("f", "fragment", "parse input as HTML fragments");
+    opts.optflag("i", "id", "output ID of elements");
+    opts.optflag("n", "name", "output name of elements");
+    opts.optflag("t", "text", "output text of elements");
+    opts.optflag("h", "help", "this cruft");
+    opts.optopt("", "install-man-page", "install real documentation", "PATH");
+
+    let args: Vec<String> = env::args().collect();
+    let matches = match opts.parse(&args[1..]) {
+        Ok(m) => m,
+        Err(f) => panic!("{}", f.to_string()),
+    };
+    if matches.opt_present("h") {
+        print!(
+            "{}",
+            opts.usage("Usage: scraper [options] SELECTOR [FILE ...]")
+        );
+        return;
+    }
+
+    if let Some(path) = matches.opt_str("install-man-page") {
+        let mut path = PathBuf::from(path);
+        if !path.ends_with("man1") {
+            path.push("man1");
+        }
+        fs::create_dir_all(&path).unwrap();
+        path.push("scraper.1");
+        fs::write(&path, &include_bytes!("../scraper.1")[..]).unwrap();
+        return;
+    }
+
+    let input = if matches.opt_present("f") {
+        Input::Fragment
+    } else {
+        Input::Document
+    };
+
+    let output = if matches.opt_present("I") {
+        Output::InnerHtml
+    } else if matches.opt_present("a") {
+        Output::Attr(matches.opt_str("a").unwrap())
+    } else if matches.opt_present("c") {
+        Output::Classes
+    } else if matches.opt_present("i") {
+        Output::Id
+    } else if matches.opt_present("n") {
+        Output::Name
+    } else if matches.opt_present("t") {
+        Output::Text
+    } else {
+        Output::Html
+    };
+
+    let selector = matches.free.first().expect("missing selector");
+    let files = &matches.free[1..];
+
+    let selector = Selector::parse(selector).unwrap();
+
+    let matched = if files.is_empty() {
+        query(&input, &output, &selector, &mut io::stdin())
+    } else {
+        files
+            .iter()
+            .map(File::open)
+            .map(Result::unwrap)
+            .any(|mut f| query(&input, &output, &selector, &mut f))
+    };
+
+    process::exit(i32::from(!matched));
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node.rs
new file mode 100644
index 000000000000..4f900857d419
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node.rs
@@ -0,0 +1,388 @@
+//! HTML nodes.
+
+use std::fmt;
+use std::ops::Deref;
+use std::slice::Iter as SliceIter;
+
+use crate::{CaseSensitivity, StrTendril};
+use html5ever::{Attribute, LocalName, QualName};
+use std::cell::OnceCell;
+
+/// An HTML node.
+// `Element` is usally the most common variant and hence boxing it
+// will most likely not improve performance overall.
+#[allow(variant_size_differences)]
+#[derive(Clone, PartialEq, Eq)]
+pub enum Node {
+    /// The document root.
+    Document,
+
+    /// The fragment root.
+    Fragment,
+
+    /// A doctype.
+    Doctype(Doctype),
+
+    /// A comment.
+    Comment(Comment),
+
+    /// Text.
+    Text(Text),
+
+    /// An element.
+    Element(Element),
+
+    /// A processing instruction.
+    ProcessingInstruction(ProcessingInstruction),
+}
+
+impl Node {
+    /// Returns true if node is the document root.
+    pub fn is_document(&self) -> bool {
+        matches!(*self, Node::Document)
+    }
+
+    /// Returns true if node is the fragment root.
+    pub fn is_fragment(&self) -> bool {
+        matches!(*self, Node::Fragment)
+    }
+
+    /// Returns true if node is a doctype.
+    pub fn is_doctype(&self) -> bool {
+        matches!(*self, Node::Doctype(_))
+    }
+
+    /// Returns true if node is a comment.
+    pub fn is_comment(&self) -> bool {
+        matches!(*self, Node::Comment(_))
+    }
+
+    /// Returns true if node is text.
+    pub fn is_text(&self) -> bool {
+        matches!(*self, Node::Text(_))
+    }
+
+    /// Returns true if node is an element.
+    pub fn is_element(&self) -> bool {
+        matches!(*self, Node::Element(_))
+    }
+
+    /// Returns self as a doctype.
+    pub fn as_doctype(&self) -> Option<&Doctype> {
+        match *self {
+            Node::Doctype(ref d) => Some(d),
+            _ => None,
+        }
+    }
+
+    /// Returns self as a comment.
+    pub fn as_comment(&self) -> Option<&Comment> {
+        match *self {
+            Node::Comment(ref c) => Some(c),
+            _ => None,
+        }
+    }
+
+    /// Returns self as text.
+    pub fn as_text(&self) -> Option<&Text> {
+        match *self {
+            Node::Text(ref t) => Some(t),
+            _ => None,
+        }
+    }
+
+    /// Returns self as an element.
+    pub fn as_element(&self) -> Option<&Element> {
+        match *self {
+            Node::Element(ref e) => Some(e),
+            _ => None,
+        }
+    }
+
+    /// Returns self as an element.
+    pub fn as_processing_instruction(&self) -> Option<&ProcessingInstruction> {
+        match *self {
+            Node::ProcessingInstruction(ref pi) => Some(pi),
+            _ => None,
+        }
+    }
+}
+
+// Always use one line.
+impl fmt::Debug for Node {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        match *self {
+            Node::Document => write!(f, "Document"),
+            Node::Fragment => write!(f, "Fragment"),
+            Node::Doctype(ref d) => write!(f, "Doctype({:?})", d),
+            Node::Comment(ref c) => write!(f, "Comment({:?})", c),
+            Node::Text(ref t) => write!(f, "Text({:?})", t),
+            Node::Element(ref e) => write!(f, "Element({:?})", e),
+            Node::ProcessingInstruction(ref pi) => write!(f, "ProcessingInstruction({:?})", pi),
+        }
+    }
+}
+
+/// A doctype.
+#[derive(Clone, PartialEq, Eq)]
+pub struct Doctype {
+    /// The doctype name.
+    pub name: StrTendril,
+
+    /// The doctype public ID.
+    pub public_id: StrTendril,
+
+    /// The doctype system ID.
+    pub system_id: StrTendril,
+}
+
+impl Doctype {
+    /// Returns the doctype name.
+    pub fn name(&self) -> &str {
+        self.name.deref()
+    }
+
+    /// Returns the doctype public ID.
+    pub fn public_id(&self) -> &str {
+        self.public_id.deref()
+    }
+
+    /// Returns the doctype system ID.
+    pub fn system_id(&self) -> &str {
+        self.system_id.deref()
+    }
+}
+
+impl fmt::Debug for Doctype {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(
+            f,
+            "<!DOCTYPE {} PUBLIC {:?} {:?}>",
+            self.name(),
+            self.public_id(),
+            self.system_id()
+        )
+    }
+}
+
+/// An HTML comment.
+#[derive(Clone, PartialEq, Eq)]
+pub struct Comment {
+    /// The comment text.
+    pub comment: StrTendril,
+}
+
+impl Deref for Comment {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        self.comment.deref()
+    }
+}
+
+impl fmt::Debug for Comment {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(f, "<!-- {:?} -->", self.deref())
+    }
+}
+
+/// HTML text.
+#[derive(Clone, PartialEq, Eq)]
+pub struct Text {
+    /// The text.
+    pub text: StrTendril,
+}
+
+impl Deref for Text {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        self.text.deref()
+    }
+}
+
+impl fmt::Debug for Text {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(f, "{:?}", self.deref())
+    }
+}
+
+/// A Map of attributes that preserves the order of the attributes.
+#[cfg(feature = "deterministic")]
+pub type Attributes = indexmap::IndexMap<QualName, StrTendril>;
+
+/// A Map of attributes that doesn't preserve the order of the attributes.
+/// Please enable the `deterministic` feature for order-preserving
+/// (de)serialization.
+#[cfg(not(feature = "deterministic"))]
+pub type Attributes = Vec<(QualName, StrTendril)>;
+
+/// An HTML element.
+#[derive(Clone, PartialEq, Eq)]
+pub struct Element {
+    /// The element name.
+    pub name: QualName,
+
+    /// The element attributes.
+    pub attrs: Attributes,
+
+    id: OnceCell<Option<StrTendril>>,
+
+    classes: OnceCell<Box<[LocalName]>>,
+}
+
+impl Element {
+    #[doc(hidden)]
+    pub fn new(name: QualName, attributes: Vec<Attribute>) -> Self {
+        #[allow(unused_mut)]
+        let mut attrs = attributes
+            .into_iter()
+            .map(|attr| (attr.name, crate::tendril_util::make(attr.value)))
+            .collect::<Attributes>();
+
+        #[cfg(not(feature = "deterministic"))]
+        attrs.sort_unstable_by(|lhs, rhs| lhs.0.cmp(&rhs.0));
+
+        Element {
+            attrs,
+            name,
+            id: OnceCell::new(),
+            classes: OnceCell::new(),
+        }
+    }
+
+    /// Returns the element name.
+    pub fn name(&self) -> &str {
+        self.name.local.deref()
+    }
+
+    /// Returns the element ID.
+    pub fn id(&self) -> Option<&str> {
+        self.id
+            .get_or_init(|| {
+                self.attrs
+                    .iter()
+                    .find(|(name, _)| name.local.as_ref() == "id")
+                    .map(|(_, value)| value.clone())
+            })
+            .as_deref()
+    }
+
+    /// Returns true if element has the class.
+    pub fn has_class(&self, class: &str, case_sensitive: CaseSensitivity) -> bool {
+        self.classes()
+            .any(|c| case_sensitive.eq(c.as_bytes(), class.as_bytes()))
+    }
+
+    /// Returns an iterator over the element's classes.
+    pub fn classes(&self) -> Classes {
+        let classes = self.classes.get_or_init(|| {
+            let mut classes = self
+                .attrs
+                .iter()
+                .filter(|(name, _)| name.local.as_ref() == "class")
+                .flat_map(|(_, value)| value.split_ascii_whitespace().map(LocalName::from))
+                .collect::<Vec<_>>();
+
+            classes.sort_unstable();
+            classes.dedup();
+
+            classes.into_boxed_slice()
+        });
+
+        Classes {
+            inner: classes.iter(),
+        }
+    }
+
+    /// Returns the value of an attribute.
+    pub fn attr(&self, attr: &str) -> Option<&str> {
+        let qualname = QualName::new(None, ns!(), LocalName::from(attr));
+
+        #[cfg(not(feature = "deterministic"))]
+        let value = self
+            .attrs
+            .binary_search_by(|attr| attr.0.cmp(&qualname))
+            .ok()
+            .map(|idx| &*self.attrs[idx].1);
+
+        #[cfg(feature = "deterministic")]
+        let value = self.attrs.get(&qualname).map(Deref::deref);
+
+        value
+    }
+
+    /// Returns an iterator over the element's attributes.
+    pub fn attrs(&self) -> Attrs {
+        Attrs {
+            inner: self.attrs.iter(),
+        }
+    }
+}
+
+/// Iterator over classes.
+#[allow(missing_debug_implementations)]
+#[derive(Clone)]
+pub struct Classes<'a> {
+    inner: SliceIter<'a, LocalName>,
+}
+
+impl<'a> Iterator for Classes<'a> {
+    type Item = &'a str;
+
+    fn next(&mut self) -> Option<&'a str> {
+        self.inner.next().map(Deref::deref)
+    }
+}
+
+/// An iterator over a node's attributes.
+#[cfg(feature = "deterministic")]
+pub type AttributesIter<'a> = indexmap::map::Iter<'a, QualName, StrTendril>;
+
+/// An iterator over a node's attributes.
+#[cfg(not(feature = "deterministic"))]
+pub type AttributesIter<'a> = SliceIter<'a, (QualName, StrTendril)>;
+
+/// Iterator over attributes.
+#[allow(missing_debug_implementations)]
+#[derive(Clone)]
+pub struct Attrs<'a> {
+    inner: AttributesIter<'a>,
+}
+
+impl<'a> Iterator for Attrs<'a> {
+    type Item = (&'a str, &'a str);
+
+    fn next(&mut self) -> Option<(&'a str, &'a str)> {
+        self.inner.next().map(|(k, v)| (k.local.deref(), v.deref()))
+    }
+}
+
+impl fmt::Debug for Element {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(f, "<{}", self.name())?;
+        for (key, value) in self.attrs() {
+            write!(f, " {}={:?}", key, value)?;
+        }
+        write!(f, ">")
+    }
+}
+
+/// HTML Processing Instruction.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ProcessingInstruction {
+    /// The PI target.
+    pub target: StrTendril,
+    /// The PI data.
+    pub data: StrTendril,
+}
+
+impl Deref for ProcessingInstruction {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        self.data.deref()
+    }
+}
+
+pub(crate) mod serializable;
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node/serializable.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node/serializable.rs
new file mode 100644
index 000000000000..b5f8183ae034
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node/serializable.rs
@@ -0,0 +1,52 @@
+use std::io::Error;
+
+use ego_tree::{iter::Edge, NodeRef};
+use html5ever::serialize::{Serializer, TraversalScope};
+
+use crate::Node;
+
+/// Serialize an HTML node using html5ever serializer.
+pub(crate) fn serialize<S: Serializer>(
+    self_node: NodeRef<Node>,
+    serializer: &mut S,
+    traversal_scope: TraversalScope,
+) -> Result<(), Error> {
+    for edge in self_node.traverse() {
+        match edge {
+            Edge::Open(node) => {
+                if node == self_node && traversal_scope == TraversalScope::ChildrenOnly(None) {
+                    continue;
+                }
+
+                match *node.value() {
+                    Node::Doctype(ref doctype) => {
+                        serializer.write_doctype(doctype.name())?;
+                    }
+                    Node::Comment(ref comment) => {
+                        serializer.write_comment(comment)?;
+                    }
+                    Node::Text(ref text) => {
+                        serializer.write_text(text)?;
+                    }
+                    Node::Element(ref elem) => {
+                        let attrs = elem.attrs.iter().map(|(k, v)| (k, &v[..]));
+                        serializer.start_elem(elem.name.clone(), attrs)?;
+                    }
+                    _ => (),
+                }
+            }
+
+            Edge::Close(node) => {
+                if node == self_node && traversal_scope == TraversalScope::ChildrenOnly(None) {
+                    continue;
+                }
+
+                if let Some(elem) = node.value().as_element() {
+                    serializer.end_elem(elem.name.clone())?;
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selectable.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selectable.rs
new file mode 100644
index 000000000000..f77a99760df9
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selectable.rs
@@ -0,0 +1,70 @@
+//! Provides the [`Selectable`] to abstract over collections of elements
+
+use crate::{
+    element_ref::{self, ElementRef},
+    html::{self, Html},
+    selector::Selector,
+};
+
+/// Trait to abstract over collections of elements to which a [CSS selector][Selector] can be applied
+///
+/// The mainly enables writing helper functions which are generic over [`Html`] and [`ElementRef`], e.g.
+///
+/// ```
+/// use scraper::{selectable::Selectable, selector::Selector};
+///
+/// fn text_of_first_match<'a, S>(selectable: S, selector: &Selector) -> Option<String>
+/// where
+///     S: Selectable<'a>,
+/// {
+///     selectable.select(selector).next().map(|element| element.text().collect())
+/// }
+/// ```
+pub trait Selectable<'a> {
+    /// Iterator over [element references][ElementRef] matching a [CSS selector[Selector]
+    type Select<'b>: Iterator<Item = ElementRef<'a>>;
+
+    /// Applies the given `selector` to the collection of elements represented by `self`
+    fn select(self, selector: &Selector) -> Self::Select<'_>;
+}
+
+impl<'a> Selectable<'a> for &'a Html {
+    type Select<'b> = html::Select<'a, 'b>;
+
+    fn select(self, selector: &Selector) -> Self::Select<'_> {
+        Html::select(self, selector)
+    }
+}
+
+impl<'a> Selectable<'a> for ElementRef<'a> {
+    type Select<'b> = element_ref::Select<'a, 'b>;
+
+    fn select(self, selector: &Selector) -> Self::Select<'_> {
+        ElementRef::select(&self, selector)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn select_one<'a, S>(selectable: S, selector: &Selector) -> Option<ElementRef<'a>>
+    where
+        S: Selectable<'a>,
+    {
+        selectable.select(selector).next()
+    }
+
+    #[test]
+    fn html_and_element_ref_are_selectable() {
+        let fragment = Html::parse_fragment(
+            r#"<select class="foo"><option value="bar">foobar</option></select>"#,
+        );
+
+        let selector = Selector::parse("select.foo").unwrap();
+        let element = select_one(&fragment, &selector).unwrap();
+
+        let selector = Selector::parse("select.foo option[value='bar']").unwrap();
+        let _element = select_one(element, &selector).unwrap();
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selector.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selector.rs
new file mode 100644
index 000000000000..4f76c2b8407c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selector.rs
@@ -0,0 +1,257 @@
+//! CSS selectors.
+
+use std::convert::TryFrom;
+use std::fmt;
+
+pub use cssparser::ToCss;
+use html5ever::{LocalName, Namespace};
+use precomputed_hash::PrecomputedHash;
+use selectors::{
+    matching,
+    parser::{self, ParseRelative, SelectorList, SelectorParseErrorKind},
+};
+
+use crate::error::SelectorErrorKind;
+use crate::ElementRef;
+
+/// Wrapper around CSS selectors.
+///
+/// Represents a "selector group", i.e. a comma-separated list of selectors.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Selector {
+    /// The CSS selectors.
+    selectors: SelectorList<Simple>,
+}
+
+impl Selector {
+    /// Parses a CSS selector group.
+    pub fn parse(selectors: &'_ str) -> Result<Self, SelectorErrorKind> {
+        let mut parser_input = cssparser::ParserInput::new(selectors);
+        let mut parser = cssparser::Parser::new(&mut parser_input);
+
+        SelectorList::parse(&Parser, &mut parser, ParseRelative::No)
+            .map(|selectors| Self { selectors })
+            .map_err(SelectorErrorKind::from)
+    }
+
+    /// Returns true if the element matches this selector.
+    pub fn matches(&self, element: &ElementRef) -> bool {
+        self.matches_with_scope(element, None)
+    }
+
+    /// Returns true if the element matches this selector.
+    /// The optional `scope` argument is used to specify which element has `:scope` pseudo-class.
+    /// When it is `None`, `:scope` will match the root element.
+    pub fn matches_with_scope(&self, element: &ElementRef, scope: Option<ElementRef>) -> bool {
+        self.matches_with_scope_and_cache(element, scope, &mut Default::default())
+    }
+
+    // The `nth_index_cache` must not be used after `self` is dropped
+    // to avoid incorrect results (even though no undefined behaviour is possible)
+    // due to the usage of selector memory addresses as cache keys.
+    pub(crate) fn matches_with_scope_and_cache(
+        &self,
+        element: &ElementRef,
+        scope: Option<ElementRef>,
+        caches: &mut matching::SelectorCaches,
+    ) -> bool {
+        let mut context = matching::MatchingContext::new(
+            matching::MatchingMode::Normal,
+            None,
+            caches,
+            matching::QuirksMode::NoQuirks,
+            matching::NeedsSelectorFlags::No,
+            matching::MatchingForInvalidation::No,
+        );
+        context.scope_element = scope.map(|x| selectors::Element::opaque(&x));
+        self.selectors
+            .slice()
+            .iter()
+            .any(|s| matching::matches_selector(s, 0, None, element, &mut context))
+    }
+}
+
+impl ToCss for Selector {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        self.selectors.to_css(dest)
+    }
+}
+
+/// An implementation of `Parser` for `selectors`
+#[derive(Clone, Copy, Debug)]
+pub struct Parser;
+impl<'i> parser::Parser<'i> for Parser {
+    type Impl = Simple;
+    type Error = SelectorParseErrorKind<'i>;
+
+    fn parse_is_and_where(&self) -> bool {
+        true
+    }
+
+    fn parse_has(&self) -> bool {
+        true
+    }
+}
+
+/// A simple implementation of `SelectorImpl` with no pseudo-classes or pseudo-elements.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Simple;
+
+impl parser::SelectorImpl for Simple {
+    type AttrValue = CssString;
+    type Identifier = CssLocalName;
+    type LocalName = CssLocalName;
+    type NamespacePrefix = CssLocalName;
+    type NamespaceUrl = Namespace;
+    type BorrowedNamespaceUrl = Namespace;
+    type BorrowedLocalName = CssLocalName;
+
+    type NonTSPseudoClass = NonTSPseudoClass;
+    type PseudoElement = PseudoElement;
+
+    // see: https://github.com/servo/servo/pull/19747#issuecomment-357106065
+    type ExtraMatchingData<'a> = ();
+}
+
+/// Wraps [`String`] so that it can be used with [`selectors`]
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct CssString(pub String);
+
+impl<'a> From<&'a str> for CssString {
+    fn from(val: &'a str) -> Self {
+        Self(val.to_owned())
+    }
+}
+
+impl AsRef<str> for CssString {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+
+impl ToCss for CssString {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        cssparser::serialize_string(&self.0, dest)
+    }
+}
+
+/// Wraps [`LocalName`] so that it can be used with [`selectors`]
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
+pub struct CssLocalName(pub LocalName);
+
+impl<'a> From<&'a str> for CssLocalName {
+    fn from(val: &'a str) -> Self {
+        Self(val.into())
+    }
+}
+
+impl ToCss for CssLocalName {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        dest.write_str(&self.0)
+    }
+}
+
+impl PrecomputedHash for CssLocalName {
+    fn precomputed_hash(&self) -> u32 {
+        self.0.precomputed_hash()
+    }
+}
+
+/// Non Tree-Structural Pseudo-Class.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum NonTSPseudoClass {}
+
+impl parser::NonTSPseudoClass for NonTSPseudoClass {
+    type Impl = Simple;
+
+    fn is_active_or_hover(&self) -> bool {
+        false
+    }
+
+    fn is_user_action_state(&self) -> bool {
+        false
+    }
+}
+
+impl ToCss for NonTSPseudoClass {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        dest.write_str("")
+    }
+}
+
+/// CSS Pseudo-Element
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PseudoElement {}
+
+impl parser::PseudoElement for PseudoElement {
+    type Impl = Simple;
+}
+
+impl ToCss for PseudoElement {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        dest.write_str("")
+    }
+}
+
+impl<'i> TryFrom<&'i str> for Selector {
+    type Error = SelectorErrorKind<'i>;
+
+    fn try_from(s: &'i str) -> Result<Self, Self::Error> {
+        Selector::parse(s)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::convert::TryInto;
+
+    #[test]
+    fn selector_conversions() {
+        let s = "#testid.testclass";
+        let _sel: Selector = s.try_into().unwrap();
+
+        let s = s.to_owned();
+        let _sel: Selector = (*s).try_into().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn invalid_selector_conversions() {
+        let s = "<failing selector>";
+        let _sel: Selector = s.try_into().unwrap();
+    }
+
+    #[test]
+    fn has_selector() {
+        let s = ":has(a)";
+        let _sel: Selector = s.try_into().unwrap();
+    }
+
+    #[test]
+    fn is_selector() {
+        let s = ":is(a)";
+        let _sel: Selector = s.try_into().unwrap();
+    }
+
+    #[test]
+    fn where_selector() {
+        let s = ":where(a)";
+        let _sel: Selector = s.try_into().unwrap();
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/test.rs b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/test.rs
new file mode 100644
index 000000000000..86d498dc01eb
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/test.rs
@@ -0,0 +1,46 @@
+use crate::{Html, Selector};
+
+#[test]
+fn tag_with_newline() {
+    let selector = Selector::parse("a").unwrap();
+
+    let document = Html::parse_fragment(
+        r#"
+        <a
+                            href="https://github.com/causal-agent/scraper">
+
+                            </a>
+        "#,
+    );
+
+    let mut iter = document.select(&selector);
+    let a = iter.next().unwrap();
+    assert_eq!(
+        a.value().attr("href"),
+        Some("https://github.com/causal-agent/scraper")
+    );
+}
+
+#[test]
+fn has_selector() {
+    let document = Html::parse_fragment(
+        r#"
+        <div>
+            <div id="foo">
+                Hi There!
+            </div>
+        </div>
+        <ul>
+            <li>first</li>
+            <li>second</li>
+            <li>third</li>
+        </ul>
+        "#,
+    );
+
+    let selector = Selector::parse("div:has(div#foo) + ul > li:nth-child(2)").unwrap();
+
+    let mut iter = document.select(&selector);
+    let li = iter.next().unwrap();
+    assert_eq!(li.inner_html(), "second");
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo_vcs_info.json
new file mode 100644
index 000000000000..b91cd6a85870
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "b73c5190f14cc570952b880432f65e3e7d7a31b6"
+  },
+  "path_in_vcs": "servo/components/selectors"
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/CHANGES.md b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/CHANGES.md
new file mode 100644
index 000000000000..b1e9511dca30
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/CHANGES.md
@@ -0,0 +1 @@
+- `parser.rs` no longer wraps values in quotes (`"..."`) but expects their `to_css` impl to already wrap it ([Gecko Bug 1854809](https://bugzilla.mozilla.org/show_bug.cgi?id=1854809))
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml
new file mode 100644
index 000000000000..3bcbb13a03db
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml
@@ -0,0 +1,88 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "selectors"
+version = "0.26.0"
+authors = ["The Servo Project Developers"]
+build = "build.rs"
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "CSS Selectors matching for Rust"
+documentation = "https://docs.rs/selectors/"
+readme = "README.md"
+keywords = [
+    "css",
+    "selectors",
+]
+license = "MPL-2.0"
+repository = "https://github.com/servo/stylo"
+
+[lib]
+name = "selectors"
+path = "lib.rs"
+
+[dependencies.bitflags]
+version = "2"
+
+[dependencies.cssparser]
+version = "0.34"
+
+[dependencies.derive_more]
+version = "0.99"
+features = [
+    "add",
+    "add_assign",
+]
+default-features = false
+
+[dependencies.fxhash]
+version = "0.2"
+
+[dependencies.log]
+version = "0.4"
+
+[dependencies.new_debug_unreachable]
+version = "1"
+
+[dependencies.phf]
+version = "0.11"
+
+[dependencies.precomputed-hash]
+version = "0.1"
+
+[dependencies.servo_arc]
+version = "0.4"
+
+[dependencies.smallvec]
+version = "1.0"
+
+[dependencies.to_shmem]
+version = "0.1"
+features = ["servo_arc"]
+optional = true
+
+[dependencies.to_shmem_derive]
+version = "0.1"
+optional = true
+
+[build-dependencies.phf_codegen]
+version = "0.11"
+
+[features]
+bench = []
+to_shmem = [
+    "dep:to_shmem",
+    "dep:to_shmem_derive",
+]
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml.orig
new file mode 100644
index 000000000000..4e495a6c6b0f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/Cargo.toml.orig
@@ -0,0 +1,37 @@
+[package]
+name = "selectors"
+version = "0.26.0"
+authors = ["The Servo Project Developers"]
+documentation = "https://docs.rs/selectors/"
+description = "CSS Selectors matching for Rust"
+repository = "https://github.com/servo/stylo"
+readme = "README.md"
+keywords = ["css", "selectors"]
+license = "MPL-2.0"
+edition = "2021"
+build = "build.rs"
+
+[lib]
+name = "selectors"
+path = "lib.rs"
+
+[features]
+bench = []
+to_shmem = ["dep:to_shmem", "dep:to_shmem_derive"]
+
+[dependencies]
+bitflags = "2"
+cssparser = "0.34"
+derive_more = { version = "0.99", default-features = false, features = ["add", "add_assign"] }
+fxhash = "0.2"
+log = "0.4"
+phf = "0.11"
+precomputed-hash = "0.1"
+servo_arc = { version = "0.4", path = "../servo_arc" }
+smallvec = "1.0"
+to_shmem = { version = "0.1", path = "../to_shmem", features = ["servo_arc"], optional = true }
+to_shmem_derive = { version = "0.1", path = "../to_shmem_derive", optional = true }
+new_debug_unreachable = "1"
+
+[build-dependencies]
+phf_codegen = "0.11"
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/README.md b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/README.md
new file mode 100644
index 000000000000..dac4a7ff91a5
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/README.md
@@ -0,0 +1,25 @@
+rust-selectors
+==============
+
+* [![Build Status](https://travis-ci.com/servo/rust-selectors.svg?branch=master)](
+  https://travis-ci.com/servo/rust-selectors)
+* [Documentation](https://docs.rs/selectors/)
+* [crates.io](https://crates.io/crates/selectors)
+
+CSS Selectors library for Rust.
+Includes parsing and serilization of selectors,
+as well as matching against a generic tree of elements.
+Pseudo-elements and most pseudo-classes are generic as well.
+
+**Warning:** breaking changes are made to this library fairly frequently
+(13 times in 2016, for example).
+However you can use this crate without updating it that often,
+old versions stay available on crates.io and Cargo will only automatically update
+to versions that are numbered as compatible.
+
+To see how to use this library with your own tree representation,
+see [Kuchiki’s `src/select.rs`](https://github.com/kuchiki-rs/kuchiki/blob/master/src/select.rs).
+(Note however that Kuchiki is not always up to date with the latest rust-selectors version,
+so that code may need to be tweaked.)
+If you don’t already have a tree data structure,
+consider using [Kuchiki](https://github.com/kuchiki-rs/kuchiki) itself.
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/attr.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/attr.rs
new file mode 100644
index 000000000000..917a50559d2f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/attr.rs
@@ -0,0 +1,196 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::parser::SelectorImpl;
+use cssparser::ToCss;
+use std::fmt;
+
+#[cfg(feature = "to_shmem")]
+use to_shmem_derive::ToShmem;
+
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct AttrSelectorWithOptionalNamespace<Impl: SelectorImpl> {
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    pub namespace: Option<NamespaceConstraint<(Impl::NamespacePrefix, Impl::NamespaceUrl)>>,
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    pub local_name: Impl::LocalName,
+    pub local_name_lower: Impl::LocalName,
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    pub operation: ParsedAttrSelectorOperation<Impl::AttrValue>,
+}
+
+impl<Impl: SelectorImpl> AttrSelectorWithOptionalNamespace<Impl> {
+    pub fn namespace(&self) -> Option<NamespaceConstraint<&Impl::NamespaceUrl>> {
+        self.namespace.as_ref().map(|ns| match ns {
+            NamespaceConstraint::Any => NamespaceConstraint::Any,
+            NamespaceConstraint::Specific((_, ref url)) => NamespaceConstraint::Specific(url),
+        })
+    }
+}
+
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum NamespaceConstraint<NamespaceUrl> {
+    Any,
+
+    /// Empty string for no namespace
+    Specific(NamespaceUrl),
+}
+
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum ParsedAttrSelectorOperation<AttrValue> {
+    Exists,
+    WithValue {
+        operator: AttrSelectorOperator,
+        case_sensitivity: ParsedCaseSensitivity,
+        value: AttrValue,
+    },
+}
+
+#[derive(Clone, Eq, PartialEq)]
+pub enum AttrSelectorOperation<AttrValue> {
+    Exists,
+    WithValue {
+        operator: AttrSelectorOperator,
+        case_sensitivity: CaseSensitivity,
+        value: AttrValue,
+    },
+}
+
+impl<AttrValue> AttrSelectorOperation<AttrValue> {
+    pub fn eval_str(&self, element_attr_value: &str) -> bool
+    where
+        AttrValue: AsRef<str>,
+    {
+        match *self {
+            AttrSelectorOperation::Exists => true,
+            AttrSelectorOperation::WithValue {
+                operator,
+                case_sensitivity,
+                ref value,
+            } => operator.eval_str(element_attr_value, value.as_ref(), case_sensitivity),
+        }
+    }
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum AttrSelectorOperator {
+    Equal,
+    Includes,
+    DashMatch,
+    Prefix,
+    Substring,
+    Suffix,
+}
+
+impl ToCss for AttrSelectorOperator {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        // https://drafts.csswg.org/cssom/#serializing-selectors
+        // See "attribute selector".
+        dest.write_str(match *self {
+            AttrSelectorOperator::Equal => "=",
+            AttrSelectorOperator::Includes => "~=",
+            AttrSelectorOperator::DashMatch => "|=",
+            AttrSelectorOperator::Prefix => "^=",
+            AttrSelectorOperator::Substring => "*=",
+            AttrSelectorOperator::Suffix => "$=",
+        })
+    }
+}
+
+impl AttrSelectorOperator {
+    pub fn eval_str(
+        self,
+        element_attr_value: &str,
+        attr_selector_value: &str,
+        case_sensitivity: CaseSensitivity,
+    ) -> bool {
+        let e = element_attr_value.as_bytes();
+        let s = attr_selector_value.as_bytes();
+        let case = case_sensitivity;
+        match self {
+            AttrSelectorOperator::Equal => case.eq(e, s),
+            AttrSelectorOperator::Prefix => {
+                !s.is_empty() && e.len() >= s.len() && case.eq(&e[..s.len()], s)
+            },
+            AttrSelectorOperator::Suffix => {
+                !s.is_empty() && e.len() >= s.len() && case.eq(&e[(e.len() - s.len())..], s)
+            },
+            AttrSelectorOperator::Substring => {
+                !s.is_empty() && case.contains(element_attr_value, attr_selector_value)
+            },
+            AttrSelectorOperator::Includes => {
+                !s.is_empty() &&
+                    element_attr_value
+                        .split(SELECTOR_WHITESPACE)
+                        .any(|part| case.eq(part.as_bytes(), s))
+            },
+            AttrSelectorOperator::DashMatch => {
+                case.eq(e, s) || (e.get(s.len()) == Some(&b'-') && case.eq(&e[..s.len()], s))
+            },
+        }
+    }
+}
+
+/// The definition of whitespace per CSS Selectors Level 3 § 4.
+pub static SELECTOR_WHITESPACE: &[char] = &[' ', '\t', '\n', '\r', '\x0C'];
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum ParsedCaseSensitivity {
+    /// 's' was specified.
+    ExplicitCaseSensitive,
+    /// 'i' was specified.
+    AsciiCaseInsensitive,
+    /// No flags were specified and HTML says this is a case-sensitive attribute.
+    CaseSensitive,
+    /// No flags were specified and HTML says this is a case-insensitive attribute.
+    AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument,
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum CaseSensitivity {
+    CaseSensitive,
+    AsciiCaseInsensitive,
+}
+
+impl CaseSensitivity {
+    pub fn eq(self, a: &[u8], b: &[u8]) -> bool {
+        match self {
+            CaseSensitivity::CaseSensitive => a == b,
+            CaseSensitivity::AsciiCaseInsensitive => a.eq_ignore_ascii_case(b),
+        }
+    }
+
+    pub fn contains(self, haystack: &str, needle: &str) -> bool {
+        match self {
+            CaseSensitivity::CaseSensitive => haystack.contains(needle),
+            CaseSensitivity::AsciiCaseInsensitive => {
+                if let Some((&n_first_byte, n_rest)) = needle.as_bytes().split_first() {
+                    haystack.bytes().enumerate().any(|(i, byte)| {
+                        if !byte.eq_ignore_ascii_case(&n_first_byte) {
+                            return false;
+                        }
+                        let after_this_byte = &haystack.as_bytes()[i + 1..];
+                        match after_this_byte.get(..n_rest.len()) {
+                            None => false,
+                            Some(haystack_slice) => haystack_slice.eq_ignore_ascii_case(n_rest),
+                        }
+                    })
+                } else {
+                    // any_str.contains("") == true,
+                    // though these cases should be handled with *NeverMatches and never go here.
+                    true
+                }
+            },
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/bloom.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/bloom.rs
new file mode 100644
index 000000000000..98461d1ba24a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/bloom.rs
@@ -0,0 +1,422 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Counting and non-counting Bloom filters tuned for use as ancestor filters
+//! for selector matching.
+
+use std::fmt::{self, Debug};
+
+// The top 8 bits of the 32-bit hash value are not used by the bloom filter.
+// Consumers may rely on this to pack hashes more efficiently.
+pub const BLOOM_HASH_MASK: u32 = 0x00ffffff;
+const KEY_SIZE: usize = 12;
+
+const ARRAY_SIZE: usize = 1 << KEY_SIZE;
+const KEY_MASK: u32 = (1 << KEY_SIZE) - 1;
+
+/// A counting Bloom filter with 8-bit counters.
+pub type BloomFilter = CountingBloomFilter<BloomStorageU8>;
+
+/// A counting Bloom filter with parameterized storage to handle
+/// counters of different sizes.  For now we assume that having two hash
+/// functions is enough, but we may revisit that decision later.
+///
+/// The filter uses an array with 2**KeySize entries.
+///
+/// Assuming a well-distributed hash function, a Bloom filter with
+/// array size M containing N elements and
+/// using k hash function has expected false positive rate exactly
+///
+/// $  (1 - (1 - 1/M)^{kN})^k  $
+///
+/// because each array slot has a
+///
+/// $  (1 - 1/M)^{kN}  $
+///
+/// chance of being 0, and the expected false positive rate is the
+/// probability that all of the k hash functions will hit a nonzero
+/// slot.
+///
+/// For reasonable assumptions (M large, kN large, which should both
+/// hold if we're worried about false positives) about M and kN this
+/// becomes approximately
+///
+/// $$  (1 - \exp(-kN/M))^k   $$
+///
+/// For our special case of k == 2, that's $(1 - \exp(-2N/M))^2$,
+/// or in other words
+///
+/// $$    N/M = -0.5 * \ln(1 - \sqrt(r))   $$
+///
+/// where r is the false positive rate.  This can be used to compute
+/// the desired KeySize for a given load N and false positive rate r.
+///
+/// If N/M is assumed small, then the false positive rate can
+/// further be approximated as 4*N^2/M^2.  So increasing KeySize by
+/// 1, which doubles M, reduces the false positive rate by about a
+/// factor of 4, and a false positive rate of 1% corresponds to
+/// about M/N == 20.
+///
+/// What this means in practice is that for a few hundred keys using a
+/// KeySize of 12 gives false positive rates on the order of 0.25-4%.
+///
+/// Similarly, using a KeySize of 10 would lead to a 4% false
+/// positive rate for N == 100 and to quite bad false positive
+/// rates for larger N.
+#[derive(Clone, Default)]
+pub struct CountingBloomFilter<S>
+where
+    S: BloomStorage,
+{
+    storage: S,
+}
+
+impl<S> CountingBloomFilter<S>
+where
+    S: BloomStorage,
+{
+    /// Creates a new bloom filter.
+    #[inline]
+    pub fn new() -> Self {
+        Default::default()
+    }
+
+    #[inline]
+    pub fn clear(&mut self) {
+        self.storage = Default::default();
+    }
+
+    // Slow linear accessor to make sure the bloom filter is zeroed. This should
+    // never be used in release builds.
+    #[cfg(debug_assertions)]
+    pub fn is_zeroed(&self) -> bool {
+        self.storage.is_zeroed()
+    }
+
+    #[cfg(not(debug_assertions))]
+    pub fn is_zeroed(&self) -> bool {
+        unreachable!()
+    }
+
+    /// Inserts an item with a particular hash into the bloom filter.
+    #[inline]
+    pub fn insert_hash(&mut self, hash: u32) {
+        self.storage.adjust_first_slot(hash, true);
+        self.storage.adjust_second_slot(hash, true);
+    }
+
+    /// Removes an item with a particular hash from the bloom filter.
+    #[inline]
+    pub fn remove_hash(&mut self, hash: u32) {
+        self.storage.adjust_first_slot(hash, false);
+        self.storage.adjust_second_slot(hash, false);
+    }
+
+    /// Check whether the filter might contain an item with the given hash.
+    /// This can sometimes return true even if the item is not in the filter,
+    /// but will never return false for items that are actually in the filter.
+    #[inline]
+    pub fn might_contain_hash(&self, hash: u32) -> bool {
+        !self.storage.first_slot_is_empty(hash) && !self.storage.second_slot_is_empty(hash)
+    }
+}
+
+impl<S> Debug for CountingBloomFilter<S>
+where
+    S: BloomStorage,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut slots_used = 0;
+        for i in 0..ARRAY_SIZE {
+            if !self.storage.slot_is_empty(i) {
+                slots_used += 1;
+            }
+        }
+        write!(f, "BloomFilter({}/{})", slots_used, ARRAY_SIZE)
+    }
+}
+
+pub trait BloomStorage: Clone + Default {
+    fn slot_is_empty(&self, index: usize) -> bool;
+    fn adjust_slot(&mut self, index: usize, increment: bool);
+    fn is_zeroed(&self) -> bool;
+
+    #[inline]
+    fn first_slot_is_empty(&self, hash: u32) -> bool {
+        self.slot_is_empty(Self::first_slot_index(hash))
+    }
+
+    #[inline]
+    fn second_slot_is_empty(&self, hash: u32) -> bool {
+        self.slot_is_empty(Self::second_slot_index(hash))
+    }
+
+    #[inline]
+    fn adjust_first_slot(&mut self, hash: u32, increment: bool) {
+        self.adjust_slot(Self::first_slot_index(hash), increment)
+    }
+
+    #[inline]
+    fn adjust_second_slot(&mut self, hash: u32, increment: bool) {
+        self.adjust_slot(Self::second_slot_index(hash), increment)
+    }
+
+    #[inline]
+    fn first_slot_index(hash: u32) -> usize {
+        hash1(hash) as usize
+    }
+
+    #[inline]
+    fn second_slot_index(hash: u32) -> usize {
+        hash2(hash) as usize
+    }
+}
+
+/// Storage class for a CountingBloomFilter that has 8-bit counters.
+pub struct BloomStorageU8 {
+    counters: [u8; ARRAY_SIZE],
+}
+
+impl BloomStorage for BloomStorageU8 {
+    #[inline]
+    fn adjust_slot(&mut self, index: usize, increment: bool) {
+        let slot = &mut self.counters[index];
+        if *slot != 0xff {
+            // full
+            if increment {
+                *slot += 1;
+            } else {
+                *slot -= 1;
+            }
+        }
+    }
+
+    #[inline]
+    fn slot_is_empty(&self, index: usize) -> bool {
+        self.counters[index] == 0
+    }
+
+    #[inline]
+    fn is_zeroed(&self) -> bool {
+        self.counters.iter().all(|x| *x == 0)
+    }
+}
+
+impl Default for BloomStorageU8 {
+    fn default() -> Self {
+        BloomStorageU8 {
+            counters: [0; ARRAY_SIZE],
+        }
+    }
+}
+
+impl Clone for BloomStorageU8 {
+    fn clone(&self) -> Self {
+        BloomStorageU8 {
+            counters: self.counters,
+        }
+    }
+}
+
+/// Storage class for a CountingBloomFilter that has 1-bit counters.
+pub struct BloomStorageBool {
+    counters: [u8; ARRAY_SIZE / 8],
+}
+
+impl BloomStorage for BloomStorageBool {
+    #[inline]
+    fn adjust_slot(&mut self, index: usize, increment: bool) {
+        let bit = 1 << (index % 8);
+        let byte = &mut self.counters[index / 8];
+
+        // Since we have only one bit for storage, decrementing it
+        // should never do anything.  Assert against an accidental
+        // decrementing of a bit that was never set.
+        assert!(
+            increment || (*byte & bit) != 0,
+            "should not decrement if slot is already false"
+        );
+
+        if increment {
+            *byte |= bit;
+        }
+    }
+
+    #[inline]
+    fn slot_is_empty(&self, index: usize) -> bool {
+        let bit = 1 << (index % 8);
+        (self.counters[index / 8] & bit) == 0
+    }
+
+    #[inline]
+    fn is_zeroed(&self) -> bool {
+        self.counters.iter().all(|x| *x == 0)
+    }
+}
+
+impl Default for BloomStorageBool {
+    fn default() -> Self {
+        BloomStorageBool {
+            counters: [0; ARRAY_SIZE / 8],
+        }
+    }
+}
+
+impl Clone for BloomStorageBool {
+    fn clone(&self) -> Self {
+        BloomStorageBool {
+            counters: self.counters,
+        }
+    }
+}
+
+#[inline]
+fn hash1(hash: u32) -> u32 {
+    hash & KEY_MASK
+}
+
+#[inline]
+fn hash2(hash: u32) -> u32 {
+    (hash >> KEY_SIZE) & KEY_MASK
+}
+
+#[test]
+fn create_and_insert_some_stuff() {
+    use fxhash::FxHasher;
+    use std::hash::{Hash, Hasher};
+    use std::mem::transmute;
+
+    fn hash_as_str(i: usize) -> u32 {
+        let mut hasher = FxHasher::default();
+        let s = i.to_string();
+        s.hash(&mut hasher);
+        let hash: u64 = hasher.finish();
+        (hash >> 32) as u32 ^ (hash as u32)
+    }
+
+    let mut bf = BloomFilter::new();
+
+    // Statically assert that ARRAY_SIZE is a multiple of 8, which
+    // BloomStorageBool relies on.
+    unsafe {
+        transmute::<[u8; ARRAY_SIZE % 8], [u8; 0]>([]);
+    }
+
+    for i in 0_usize..1000 {
+        bf.insert_hash(hash_as_str(i));
+    }
+
+    for i in 0_usize..1000 {
+        assert!(bf.might_contain_hash(hash_as_str(i)));
+    }
+
+    let false_positives = (1001_usize..2000)
+        .filter(|i| bf.might_contain_hash(hash_as_str(*i)))
+        .count();
+
+    assert!(false_positives < 190, "{} is not < 190", false_positives); // 19%.
+
+    for i in 0_usize..100 {
+        bf.remove_hash(hash_as_str(i));
+    }
+
+    for i in 100_usize..1000 {
+        assert!(bf.might_contain_hash(hash_as_str(i)));
+    }
+
+    let false_positives = (0_usize..100)
+        .filter(|i| bf.might_contain_hash(hash_as_str(*i)))
+        .count();
+
+    assert!(false_positives < 20, "{} is not < 20", false_positives); // 20%.
+
+    bf.clear();
+
+    for i in 0_usize..2000 {
+        assert!(!bf.might_contain_hash(hash_as_str(i)));
+    }
+}
+
+#[cfg(feature = "bench")]
+#[cfg(test)]
+mod bench {
+    extern crate test;
+    use super::BloomFilter;
+
+    #[derive(Default)]
+    struct HashGenerator(u32);
+
+    impl HashGenerator {
+        fn next(&mut self) -> u32 {
+            // Each hash is split into two twelve-bit segments, which are used
+            // as an index into an array. We increment each by 64 so that we
+            // hit the next cache line, and then another 1 so that our wrapping
+            // behavior leads us to different entries each time.
+            //
+            // Trying to simulate cold caches is rather difficult with the cargo
+            // benchmarking setup, so it may all be moot depending on the number
+            // of iterations that end up being run. But we might as well.
+            self.0 += (65) + (65 << super::KEY_SIZE);
+            self.0
+        }
+    }
+
+    #[bench]
+    fn create_insert_1000_remove_100_lookup_100(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut gen1 = HashGenerator::default();
+            let mut gen2 = HashGenerator::default();
+            let mut bf = BloomFilter::new();
+            for _ in 0_usize..1000 {
+                bf.insert_hash(gen1.next());
+            }
+            for _ in 0_usize..100 {
+                bf.remove_hash(gen2.next());
+            }
+            for _ in 100_usize..200 {
+                test::black_box(bf.might_contain_hash(gen2.next()));
+            }
+        });
+    }
+
+    #[bench]
+    fn might_contain_10(b: &mut test::Bencher) {
+        let bf = BloomFilter::new();
+        let mut gen = HashGenerator::default();
+        b.iter(|| {
+            for _ in 0..10 {
+                test::black_box(bf.might_contain_hash(gen.next()));
+            }
+        });
+    }
+
+    #[bench]
+    fn clear(b: &mut test::Bencher) {
+        let mut bf = Box::new(BloomFilter::new());
+        b.iter(|| test::black_box(&mut bf).clear());
+    }
+
+    #[bench]
+    fn insert_10(b: &mut test::Bencher) {
+        let mut bf = BloomFilter::new();
+        let mut gen = HashGenerator::default();
+        b.iter(|| {
+            for _ in 0..10 {
+                test::black_box(bf.insert_hash(gen.next()));
+            }
+        });
+    }
+
+    #[bench]
+    fn remove_10(b: &mut test::Bencher) {
+        let mut bf = BloomFilter::new();
+        let mut gen = HashGenerator::default();
+        // Note: this will underflow, and that's ok.
+        b.iter(|| {
+            for _ in 0..10 {
+                bf.remove_hash(gen.next())
+            }
+        });
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs
new file mode 100644
index 000000000000..c5c3803991ef
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs
@@ -0,0 +1,77 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+extern crate phf_codegen;
+
+use std::env;
+use std::fs::File;
+use std::io::{BufWriter, Write};
+use std::path::Path;
+
+fn main() {
+    let path = Path::new(&env::var_os("OUT_DIR").unwrap())
+        .join("ascii_case_insensitive_html_attributes.rs");
+    let mut file = BufWriter::new(File::create(&path).unwrap());
+
+    let mut set = phf_codegen::Set::new();
+    for name in ASCII_CASE_INSENSITIVE_HTML_ATTRIBUTES.split_whitespace() {
+        set.entry(name);
+    }
+    write!(
+        &mut file,
+        "{{ static SET: ::phf::Set<&'static str> = {}; &SET }}",
+        set.build(),
+    )
+    .unwrap();
+}
+
+/// <https://html.spec.whatwg.org/multipage/#selectors>
+static ASCII_CASE_INSENSITIVE_HTML_ATTRIBUTES: &str = r#"
+    accept
+    accept-charset
+    align
+    alink
+    axis
+    bgcolor
+    charset
+    checked
+    clear
+    codetype
+    color
+    compact
+    declare
+    defer
+    dir
+    direction
+    disabled
+    enctype
+    face
+    frame
+    hreflang
+    http-equiv
+    lang
+    language
+    link
+    media
+    method
+    multiple
+    nohref
+    noresize
+    noshade
+    nowrap
+    readonly
+    rel
+    rev
+    rules
+    scope
+    scrolling
+    selected
+    shape
+    target
+    text
+    type
+    valign
+    valuetype
+    vlink
+"#;
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/builder.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/builder.rs
new file mode 100644
index 000000000000..bbff1c2e5111
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/builder.rs
@@ -0,0 +1,425 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Helper module to build up a selector safely and efficiently.
+//!
+//! Our selector representation is designed to optimize matching, and has
+//! several requirements:
+//! * All simple selectors and combinators are stored inline in the same buffer as Component
+//!   instances.
+//! * We store the top-level compound selectors from right to left, i.e. in matching order.
+//! * We store the simple selectors for each combinator from left to right, so that we match the
+//!   cheaper simple selectors first.
+//!
+//! For example, the selector:
+//!
+//!   .bar:hover > .baz:nth-child(2) + .qux
+//!
+//! Gets stored as:
+//!
+//!   [.qux,  + , .baz, :nth-child(2),  > , .bar, :hover]
+//!
+//! Meeting all these constraints without extra memmove traffic during parsing is non-trivial. This
+//! module encapsulates those details and presents an easy-to-use API for the parser.
+
+use crate::parser::{Combinator, Component, RelativeSelector, Selector, SelectorImpl, ParseRelative};
+use crate::sink::Push;
+use servo_arc::{Arc, ThinArc};
+use smallvec::SmallVec;
+use std::cmp;
+use std::slice;
+use bitflags::bitflags;
+use derive_more::{Add, AddAssign};
+
+#[cfg(feature = "to_shmem")]
+use to_shmem_derive::ToShmem;
+
+/// Top-level SelectorBuilder struct. This should be stack-allocated by the consumer and never
+/// moved (because it contains a lot of inline data that would be slow to memmove).
+///
+/// After instantiation, callers may call the push_simple_selector() and push_combinator() methods
+/// to append selector data as it is encountered (from left to right). Once the process is
+/// complete, callers should invoke build(), which transforms the contents of the SelectorBuilder
+/// into a heap- allocated Selector and leaves the builder in a drained state.
+#[derive(Debug)]
+pub struct SelectorBuilder<Impl: SelectorImpl> {
+    /// The entire sequence of components. We make this large because the result of parsing a
+    /// selector is fed into a new Arc-ed allocation, so any spilled vec would be a wasted
+    /// allocation. Also, Components are large enough that we don't have much cache locality
+    /// benefit from reserving stack space for fewer of them.
+    components: SmallVec<[Component<Impl>; 32]>,
+    last_compound_start: Option<usize>,
+}
+
+impl<Impl: SelectorImpl> Push<Component<Impl>> for SelectorBuilder<Impl> {
+    fn push(&mut self, value: Component<Impl>) {
+        self.push_simple_selector(value);
+    }
+}
+
+impl<Impl: SelectorImpl> SelectorBuilder<Impl> {
+    /// Pushes a simple selector onto the current compound selector.
+    #[inline(always)]
+    pub fn push_simple_selector(&mut self, ss: Component<Impl>) {
+        debug_assert!(!ss.is_combinator());
+        self.components.push(ss);
+    }
+
+    /// Completes the current compound selector and starts a new one, delimited by the given
+    /// combinator.
+    #[inline(always)]
+    pub fn push_combinator(&mut self, c: Combinator) {
+        self.reverse_last_compound();
+        self.components.push(Component::Combinator(c));
+        self.last_compound_start = Some(self.components.len());
+    }
+
+    fn reverse_last_compound(&mut self) {
+        let start = self.last_compound_start.unwrap_or(0);
+        self.components[start..].reverse();
+    }
+
+    /// Returns true if combinators have ever been pushed to this builder.
+    #[inline(always)]
+    pub fn has_combinators(&self) -> bool {
+        self.last_compound_start.is_some()
+    }
+
+    /// Consumes the builder, producing a Selector.
+    #[inline(always)]
+    pub fn build(&mut self, parse_relative: ParseRelative) -> ThinArc<SpecificityAndFlags, Component<Impl>> {
+        // Compute the specificity and flags.
+        let sf = specificity_and_flags(self.components.iter());
+        self.build_with_specificity_and_flags(sf, parse_relative)
+    }
+
+    /// Builds with an explicit SpecificityAndFlags. This is separated from build() so that unit
+    /// tests can pass an explicit specificity.
+    #[inline(always)]
+    pub(crate) fn build_with_specificity_and_flags(
+        &mut self,
+        mut spec: SpecificityAndFlags,
+        parse_relative: ParseRelative,
+    ) -> ThinArc<SpecificityAndFlags, Component<Impl>> {
+        let implicit_addition = match parse_relative {
+            ParseRelative::ForNesting if !spec.flags.intersects(SelectorFlags::HAS_PARENT) => Some((Component::ParentSelector, SelectorFlags::HAS_PARENT)),
+            ParseRelative::ForScope if !spec.flags.intersects(SelectorFlags::HAS_SCOPE | SelectorFlags::HAS_PARENT) => Some((Component::ImplicitScope, SelectorFlags::HAS_SCOPE)),
+            _ => None,
+        };
+        let implicit_selector_and_combinator;
+        let implicit_selector = if let Some((component, flag)) = implicit_addition {
+            spec.flags.insert(flag);
+            implicit_selector_and_combinator = [
+                Component::Combinator(Combinator::Descendant),
+                component,
+            ];
+            &implicit_selector_and_combinator[..]
+        } else {
+            &[]
+        };
+
+        // As an optimization, for a selector without combinators, we can just keep the order
+        // as-is.
+        if self.last_compound_start.is_none() {
+            return Arc::from_header_and_iter(spec, ExactChain(self.components.drain(..), implicit_selector.iter().cloned()));
+        }
+
+        self.reverse_last_compound();
+        Arc::from_header_and_iter(spec, ExactChain(self.components.drain(..).rev(), implicit_selector.iter().cloned()))
+    }
+}
+
+
+impl<Impl: SelectorImpl> Default for SelectorBuilder<Impl> {
+    #[inline(always)]
+    fn default() -> Self {
+        SelectorBuilder {
+            components: SmallVec::new(),
+            last_compound_start: None,
+        }
+    }
+}
+
+// This is effectively a Chain<>, but Chain isn't an ExactSizeIterator, see
+// https://github.com/rust-lang/rust/issues/34433
+struct ExactChain<A, B>(A, B);
+
+impl<A, B, Item> ExactSizeIterator for ExactChain<A, B>
+where
+    A: ExactSizeIterator<Item = Item>,
+    B: ExactSizeIterator<Item = Item>,
+{
+    fn len(&self) -> usize {
+        self.0.len() + self.1.len()
+    }
+}
+
+impl<A, B, Item> Iterator for ExactChain<A, B>
+where
+    A: ExactSizeIterator<Item = Item>,
+    B: ExactSizeIterator<Item = Item>,
+{
+    type Item = Item;
+
+    #[inline(always)]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next().or_else(|| self.1.next())
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len();
+        (len, Some(len))
+    }
+}
+
+/// Flags that indicate at which point of parsing a selector are we.
+#[derive(Clone, Copy, Default, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub(crate) struct SelectorFlags(u8);
+
+bitflags! {
+    impl SelectorFlags: u8 {
+        const HAS_PSEUDO = 1 << 0;
+        const HAS_SLOTTED = 1 << 1;
+        const HAS_PART = 1 << 2;
+        const HAS_PARENT = 1 << 3;
+        const HAS_NON_FEATURELESS_COMPONENT = 1 << 4;
+        const HAS_HOST = 1 << 5;
+        const HAS_SCOPE = 1 << 6;
+    }
+}
+
+impl core::fmt::Debug for SelectorFlags {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        if self.is_empty() {
+            write!(f, "{:#x}", Self::empty().bits())
+        } else {
+            bitflags::parser::to_writer(self, f)
+        }
+    }
+}
+
+impl SelectorFlags {
+    /// When you nest a pseudo-element with something like:
+    ///
+    ///   ::before { & { .. } }
+    ///
+    /// It is not supposed to work, because :is(::before) is invalid. We can't propagate the
+    /// pseudo-flags from inner to outer selectors, to avoid breaking our invariants.
+    pub(crate) fn for_nesting() -> Self {
+        Self::all() - (Self::HAS_PSEUDO | Self::HAS_SLOTTED | Self::HAS_PART)
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub struct SpecificityAndFlags {
+    /// There are two free bits here, since we use ten bits for each specificity
+    /// kind (id, class, element).
+    pub(crate) specificity: u32,
+    /// There's padding after this field due to the size of the flags.
+    pub(crate) flags: SelectorFlags,
+}
+
+const MAX_10BIT: u32 = (1u32 << 10) - 1;
+
+#[derive(Add, AddAssign, Clone, Copy, Default, Eq, Ord, PartialEq, PartialOrd)]
+pub(crate) struct Specificity {
+    id_selectors: u32,
+    class_like_selectors: u32,
+    element_selectors: u32,
+}
+
+impl Specificity {
+    // Return the specficity of a single class-like selector.
+    #[inline]
+    pub fn single_class_like() -> Self {
+        Specificity {
+            id_selectors: 0,
+            class_like_selectors: 1,
+            element_selectors: 0,
+        }
+    }
+}
+
+impl From<u32> for Specificity {
+    #[inline]
+    fn from(value: u32) -> Specificity {
+        assert!(value <= MAX_10BIT << 20 | MAX_10BIT << 10 | MAX_10BIT);
+        Specificity {
+            id_selectors: value >> 20,
+            class_like_selectors: (value >> 10) & MAX_10BIT,
+            element_selectors: value & MAX_10BIT,
+        }
+    }
+}
+
+impl From<Specificity> for u32 {
+    #[inline]
+    fn from(specificity: Specificity) -> u32 {
+        cmp::min(specificity.id_selectors, MAX_10BIT) << 20 |
+            cmp::min(specificity.class_like_selectors, MAX_10BIT) << 10 |
+            cmp::min(specificity.element_selectors, MAX_10BIT)
+    }
+}
+
+fn specificity_and_flags<Impl>(
+    iter: slice::Iter<Component<Impl>>,
+) -> SpecificityAndFlags
+where
+    Impl: SelectorImpl,
+{
+    complex_selector_specificity_and_flags(iter).into()
+}
+
+fn complex_selector_specificity_and_flags<Impl>(
+    iter: slice::Iter<Component<Impl>>,
+) -> SpecificityAndFlags
+where
+    Impl: SelectorImpl,
+{
+    fn component_specificity<Impl>(
+        simple_selector: &Component<Impl>,
+        specificity: &mut Specificity,
+        flags: &mut SelectorFlags,
+    ) where
+        Impl: SelectorImpl,
+    {
+        match *simple_selector {
+            Component::Combinator(..) => {},
+            Component::ParentSelector => flags.insert(SelectorFlags::HAS_PARENT),
+            Component::Part(..) => {
+                flags.insert(SelectorFlags::HAS_PART);
+                specificity.element_selectors += 1
+            },
+            Component::PseudoElement(ref pseudo) => {
+                use crate::parser::PseudoElement;
+                flags.insert(SelectorFlags::HAS_PSEUDO);
+                specificity.element_selectors += pseudo.specificity_count();
+            },
+            Component::LocalName(..) => {
+                flags.insert(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+                specificity.element_selectors += 1
+            },
+            Component::Slotted(ref selector) => {
+                flags.insert(
+                    SelectorFlags::HAS_SLOTTED | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                );
+                specificity.element_selectors += 1;
+                // Note that due to the way ::slotted works we only compete with
+                // other ::slotted rules, so the above rule doesn't really
+                // matter, but we do it still for consistency with other
+                // pseudo-elements.
+                //
+                // See: https://github.com/w3c/csswg-drafts/issues/1915
+                *specificity += Specificity::from(selector.specificity());
+                flags.insert(selector.flags());
+            },
+            Component::Host(ref selector) => {
+                flags.insert(SelectorFlags::HAS_HOST);
+                specificity.class_like_selectors += 1;
+                if let Some(ref selector) = *selector {
+                    // See: https://github.com/w3c/csswg-drafts/issues/1915
+                    *specificity += Specificity::from(selector.specificity());
+                    flags.insert(selector.flags() - SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+                }
+            },
+            Component::ID(..) => {
+                flags.insert(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+                specificity.id_selectors += 1;
+            },
+            Component::Class(..) |
+            Component::AttributeInNoNamespace { .. } |
+            Component::AttributeInNoNamespaceExists { .. } |
+            Component::AttributeOther(..) |
+            Component::Root |
+            Component::Empty |
+            Component::Nth(..) |
+            Component::NonTSPseudoClass(..) => {
+                flags.insert(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+                specificity.class_like_selectors += 1;
+            },
+            Component::Scope | Component::ImplicitScope => {
+                flags.insert(SelectorFlags::HAS_SCOPE);
+                if matches!(*simple_selector, Component::Scope) {
+                    specificity.class_like_selectors += 1;
+                }
+            },
+            Component::NthOf(ref nth_of_data) => {
+                // https://drafts.csswg.org/selectors/#specificity-rules:
+                //
+                //     The specificity of the :nth-last-child() pseudo-class,
+                //     like the :nth-child() pseudo-class, combines the
+                //     specificity of a regular pseudo-class with that of its
+                //     selector argument S.
+                specificity.class_like_selectors += 1;
+                let sf = selector_list_specificity_and_flags(nth_of_data.selectors().iter());
+                *specificity += Specificity::from(sf.specificity);
+                flags.insert(sf.flags | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+            },
+            // https://drafts.csswg.org/selectors/#specificity-rules:
+            //
+            //     The specificity of an :is(), :not(), or :has() pseudo-class
+            //     is replaced by the specificity of the most specific complex
+            //     selector in its selector list argument.
+            Component::Where(ref list) |
+            Component::Negation(ref list) |
+            Component::Is(ref list) => {
+                let sf = selector_list_specificity_and_flags(list.slice().iter());
+                if !matches!(*simple_selector, Component::Where(..)) {
+                    *specificity += Specificity::from(sf.specificity);
+                }
+                flags.insert(sf.flags);
+            },
+            Component::Has(ref relative_selectors) => {
+                let sf = relative_selector_list_specificity_and_flags(relative_selectors);
+                *specificity += Specificity::from(sf.specificity);
+                flags.insert(sf.flags | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+            },
+            Component::ExplicitUniversalType |
+            Component::ExplicitAnyNamespace |
+            Component::ExplicitNoNamespace |
+            Component::DefaultNamespace(..) |
+            Component::Namespace(..) |
+            Component::RelativeSelectorAnchor |
+            Component::Invalid(..) => {
+                // Does not affect specificity
+                flags.insert(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT);
+            },
+        }
+    }
+
+    let mut specificity = Default::default();
+    let mut flags = Default::default();
+    for simple_selector in iter {
+        component_specificity(
+            &simple_selector,
+            &mut specificity,
+            &mut flags,
+        );
+    }
+    SpecificityAndFlags {
+        specificity: specificity.into(),
+        flags,
+    }
+}
+
+/// Finds the maximum specificity of elements in the list and returns it.
+pub(crate) fn selector_list_specificity_and_flags<'a, Impl: SelectorImpl>(
+    itr: impl Iterator<Item = &'a Selector<Impl>>,
+) -> SpecificityAndFlags {
+    let mut specificity = 0;
+    let mut flags = SelectorFlags::empty();
+    for selector in itr {
+        specificity = std::cmp::max(specificity, selector.specificity());
+        flags.insert(selector.flags());
+    }
+    SpecificityAndFlags { specificity, flags }
+}
+
+pub(crate) fn relative_selector_list_specificity_and_flags<Impl: SelectorImpl>(
+    list: &[RelativeSelector<Impl>],
+) -> SpecificityAndFlags {
+    selector_list_specificity_and_flags(list.iter().map(|rel| &rel.selector))
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/context.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/context.rs
new file mode 100644
index 000000000000..70db5efa05a8
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/context.rs
@@ -0,0 +1,466 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::attr::CaseSensitivity;
+use crate::bloom::BloomFilter;
+use crate::nth_index_cache::{NthIndexCache, NthIndexCacheInner};
+use crate::parser::{Selector, SelectorImpl};
+use crate::relative_selector::cache::RelativeSelectorCache;
+use crate::relative_selector::filter::RelativeSelectorFilterMap;
+use crate::tree::{Element, OpaqueElement};
+
+/// What kind of selector matching mode we should use.
+///
+/// There are two modes of selector matching. The difference is only noticeable
+/// in presence of pseudo-elements.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum MatchingMode {
+    /// Don't ignore any pseudo-element selectors.
+    Normal,
+
+    /// Ignores any stateless pseudo-element selectors in the rightmost sequence
+    /// of simple selectors.
+    ///
+    /// This is useful, for example, to match against ::before when you aren't a
+    /// pseudo-element yourself.
+    ///
+    /// For example, in presence of `::before:hover`, it would never match, but
+    /// `::before` would be ignored as in "matching".
+    ///
+    /// It's required for all the selectors you match using this mode to have a
+    /// pseudo-element.
+    ForStatelessPseudoElement,
+}
+
+/// The mode to use when matching unvisited and visited links.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum VisitedHandlingMode {
+    /// All links are matched as if they are unvisted.
+    AllLinksUnvisited,
+    /// All links are matched as if they are visited and unvisited (both :link
+    /// and :visited match).
+    ///
+    /// This is intended to be used from invalidation code, to be conservative
+    /// about whether we need to restyle a link.
+    AllLinksVisitedAndUnvisited,
+    /// A element's "relevant link" is the element being matched if it is a link
+    /// or the nearest ancestor link. The relevant link is matched as though it
+    /// is visited, and all other links are matched as if they are unvisited.
+    RelevantLinkVisited,
+}
+
+impl VisitedHandlingMode {
+    #[inline]
+    pub fn matches_visited(&self) -> bool {
+        matches!(
+            *self,
+            VisitedHandlingMode::RelevantLinkVisited |
+                VisitedHandlingMode::AllLinksVisitedAndUnvisited
+        )
+    }
+
+    #[inline]
+    pub fn matches_unvisited(&self) -> bool {
+        matches!(
+            *self,
+            VisitedHandlingMode::AllLinksUnvisited |
+                VisitedHandlingMode::AllLinksVisitedAndUnvisited
+        )
+    }
+}
+
+/// The mode to use whether we should matching rules inside @starting-style.
+/// https://drafts.csswg.org/css-transitions-2/#starting-style
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum IncludeStartingStyle {
+    /// All without rules inside @starting-style. This is for the most common case because the
+    /// primary/pseudo styles doesn't use rules inside @starting-style.
+    No,
+    /// Get the starting style. The starting style for an element as the after-change style with
+    /// @starting-style rules applied in addition. In other words, this matches all rules,
+    /// including rules inside @starting-style.
+    Yes,
+}
+
+/// Whether we need to set selector invalidation flags on elements for this
+/// match request.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum NeedsSelectorFlags {
+    No,
+    Yes,
+}
+
+/// Whether we're matching in the contect of invalidation.
+#[derive(Clone, Copy, PartialEq)]
+pub enum MatchingForInvalidation {
+    No,
+    Yes,
+    YesForComparison,
+}
+
+impl MatchingForInvalidation {
+    /// Are we matching for invalidation?
+    pub fn is_for_invalidation(&self) -> bool {
+        matches!(*self, Self::Yes | Self::YesForComparison)
+    }
+}
+
+/// Which quirks mode is this document in.
+///
+/// See: https://quirks.spec.whatwg.org/
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub enum QuirksMode {
+    /// Quirks mode.
+    Quirks,
+    /// Limited quirks mode.
+    LimitedQuirks,
+    /// No quirks mode.
+    NoQuirks,
+}
+
+impl QuirksMode {
+    #[inline]
+    pub fn classes_and_ids_case_sensitivity(self) -> CaseSensitivity {
+        match self {
+            QuirksMode::NoQuirks | QuirksMode::LimitedQuirks => CaseSensitivity::CaseSensitive,
+            QuirksMode::Quirks => CaseSensitivity::AsciiCaseInsensitive,
+        }
+    }
+}
+
+/// Set of caches (And cache-likes) that speed up expensive selector matches.
+#[derive(Default)]
+pub struct SelectorCaches {
+    /// A cache to speed up nth-index-like selectors.
+    pub nth_index: NthIndexCache,
+    /// A cache to speed up relative selector matches. See module documentation.
+    pub relative_selector: RelativeSelectorCache,
+    /// A map of bloom filters to fast-reject relative selector matches.
+    pub relative_selector_filter_map: RelativeSelectorFilterMap,
+}
+
+/// Data associated with the matching process for a element.  This context is
+/// used across many selectors for an element, so it's not appropriate for
+/// transient data that applies to only a single selector.
+pub struct MatchingContext<'a, Impl>
+where
+    Impl: SelectorImpl,
+{
+    /// Input with the matching mode we should use when matching selectors.
+    matching_mode: MatchingMode,
+    /// Input with the bloom filter used to fast-reject selectors.
+    pub bloom_filter: Option<&'a BloomFilter>,
+    /// The element which is going to match :scope pseudo-class. It can be
+    /// either one :scope element, or the scoping element.
+    ///
+    /// Note that, although in theory there can be multiple :scope elements,
+    /// in current specs, at most one is specified, and when there is one,
+    /// scoping element is not relevant anymore, so we use a single field for
+    /// them.
+    ///
+    /// When this is None, :scope will match the root element.
+    ///
+    /// See https://drafts.csswg.org/selectors-4/#scope-pseudo
+    pub scope_element: Option<OpaqueElement>,
+
+    /// The current shadow host we're collecting :host rules for.
+    pub current_host: Option<OpaqueElement>,
+
+    /// Controls how matching for links is handled.
+    visited_handling: VisitedHandlingMode,
+
+    /// Controls if we should match rules in @starting-style.
+    pub include_starting_style: IncludeStartingStyle,
+
+    /// Whether there are any rules inside @starting-style.
+    pub has_starting_style: bool,
+
+    /// The current nesting level of selectors that we're matching.
+    nesting_level: usize,
+
+    /// Whether we're inside a negation or not.
+    in_negation: bool,
+
+    /// An optional hook function for checking whether a pseudo-element
+    /// should match when matching_mode is ForStatelessPseudoElement.
+    pub pseudo_element_matching_fn: Option<&'a dyn Fn(&Impl::PseudoElement) -> bool>,
+
+    /// Extra implementation-dependent matching data.
+    pub extra_data: Impl::ExtraMatchingData<'a>,
+
+    /// The current element we're anchoring on for evaluating the relative selector.
+    current_relative_selector_anchor: Option<OpaqueElement>,
+
+    quirks_mode: QuirksMode,
+    needs_selector_flags: NeedsSelectorFlags,
+
+    /// Whether we're matching in the contect of invalidation.
+    matching_for_invalidation: MatchingForInvalidation,
+
+    /// Caches to speed up expensive selector matches.
+    pub selector_caches: &'a mut SelectorCaches,
+
+    classes_and_ids_case_sensitivity: CaseSensitivity,
+    _impl: ::std::marker::PhantomData<Impl>,
+}
+
+impl<'a, Impl> MatchingContext<'a, Impl>
+where
+    Impl: SelectorImpl,
+{
+    /// Constructs a new `MatchingContext`.
+    pub fn new(
+        matching_mode: MatchingMode,
+        bloom_filter: Option<&'a BloomFilter>,
+        selector_caches: &'a mut SelectorCaches,
+        quirks_mode: QuirksMode,
+        needs_selector_flags: NeedsSelectorFlags,
+        matching_for_invalidation: MatchingForInvalidation,
+    ) -> Self {
+        Self::new_for_visited(
+            matching_mode,
+            bloom_filter,
+            selector_caches,
+            VisitedHandlingMode::AllLinksUnvisited,
+            IncludeStartingStyle::No,
+            quirks_mode,
+            needs_selector_flags,
+            matching_for_invalidation,
+        )
+    }
+
+    /// Constructs a new `MatchingContext` for use in visited matching.
+    pub fn new_for_visited(
+        matching_mode: MatchingMode,
+        bloom_filter: Option<&'a BloomFilter>,
+        selector_caches: &'a mut SelectorCaches,
+        visited_handling: VisitedHandlingMode,
+        include_starting_style: IncludeStartingStyle,
+        quirks_mode: QuirksMode,
+        needs_selector_flags: NeedsSelectorFlags,
+        matching_for_invalidation: MatchingForInvalidation,
+    ) -> Self {
+        Self {
+            matching_mode,
+            bloom_filter,
+            visited_handling,
+            include_starting_style,
+            has_starting_style: false,
+            quirks_mode,
+            classes_and_ids_case_sensitivity: quirks_mode.classes_and_ids_case_sensitivity(),
+            needs_selector_flags,
+            matching_for_invalidation,
+            scope_element: None,
+            current_host: None,
+            nesting_level: 0,
+            in_negation: false,
+            pseudo_element_matching_fn: None,
+            extra_data: Default::default(),
+            current_relative_selector_anchor: None,
+            selector_caches,
+            _impl: ::std::marker::PhantomData,
+        }
+    }
+
+    // Grab a reference to the appropriate cache.
+    #[inline]
+    pub fn nth_index_cache(
+        &mut self,
+        is_of_type: bool,
+        is_from_end: bool,
+        selectors: &[Selector<Impl>],
+    ) -> &mut NthIndexCacheInner {
+        self.selector_caches
+            .nth_index
+            .get(is_of_type, is_from_end, selectors)
+    }
+
+    /// Whether we're matching a nested selector.
+    #[inline]
+    pub fn is_nested(&self) -> bool {
+        self.nesting_level != 0
+    }
+
+    /// Whether we're matching inside a :not(..) selector.
+    #[inline]
+    pub fn in_negation(&self) -> bool {
+        self.in_negation
+    }
+
+    /// The quirks mode of the document.
+    #[inline]
+    pub fn quirks_mode(&self) -> QuirksMode {
+        self.quirks_mode
+    }
+
+    /// The matching-mode for this selector-matching operation.
+    #[inline]
+    pub fn matching_mode(&self) -> MatchingMode {
+        self.matching_mode
+    }
+
+    /// Whether we need to set selector flags.
+    #[inline]
+    pub fn needs_selector_flags(&self) -> bool {
+        self.needs_selector_flags == NeedsSelectorFlags::Yes
+    }
+
+    /// Whether or not we're matching to invalidate.
+    #[inline]
+    pub fn matching_for_invalidation(&self) -> bool {
+        self.matching_for_invalidation.is_for_invalidation()
+    }
+
+    /// Whether or not we're comparing for invalidation, if we are matching for invalidation.
+    #[inline]
+    pub fn matching_for_invalidation_comparison(&self) -> Option<bool> {
+        match self.matching_for_invalidation {
+            MatchingForInvalidation::No => None,
+            MatchingForInvalidation::Yes => Some(false),
+            MatchingForInvalidation::YesForComparison => Some(true),
+        }
+    }
+
+    /// Run the given matching function for before/after invalidation comparison.
+    #[inline]
+    pub fn for_invalidation_comparison<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        debug_assert!(self.matching_for_invalidation(), "Not matching for invalidation?");
+        let prev = self.matching_for_invalidation;
+        self.matching_for_invalidation = MatchingForInvalidation::YesForComparison;
+        let result = f(self);
+        self.matching_for_invalidation = prev;
+        result
+    }
+
+    /// The case-sensitivity for class and ID selectors
+    #[inline]
+    pub fn classes_and_ids_case_sensitivity(&self) -> CaseSensitivity {
+        self.classes_and_ids_case_sensitivity
+    }
+
+    /// Runs F with a deeper nesting level.
+    #[inline]
+    pub fn nest<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        self.nesting_level += 1;
+        let result = f(self);
+        self.nesting_level -= 1;
+        result
+    }
+
+    /// Runs F with a deeper nesting level, and marking ourselves in a negation,
+    /// for a :not(..) selector, for example.
+    #[inline]
+    pub fn nest_for_negation<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        let old_in_negation = self.in_negation;
+        self.in_negation = true;
+        let result = self.nest(f);
+        self.in_negation = old_in_negation;
+        result
+    }
+
+    #[inline]
+    pub fn visited_handling(&self) -> VisitedHandlingMode {
+        self.visited_handling
+    }
+
+    /// Runs F with a different VisitedHandlingMode.
+    #[inline]
+    pub fn with_visited_handling_mode<F, R>(
+        &mut self,
+        handling_mode: VisitedHandlingMode,
+        f: F,
+    ) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        let original_handling_mode = self.visited_handling;
+        self.visited_handling = handling_mode;
+        let result = f(self);
+        self.visited_handling = original_handling_mode;
+        result
+    }
+
+    /// Runs F with a given shadow host which is the root of the tree whose
+    /// rules we're matching.
+    #[inline]
+    pub fn with_shadow_host<F, E, R>(&mut self, host: Option<E>, f: F) -> R
+    where
+        E: Element,
+        F: FnOnce(&mut Self) -> R,
+    {
+        let original_host = self.current_host.take();
+        self.current_host = host.map(|h| h.opaque());
+        let result = f(self);
+        self.current_host = original_host;
+        result
+    }
+
+    /// Returns the current shadow host whose shadow root we're matching rules
+    /// against.
+    #[inline]
+    pub fn shadow_host(&self) -> Option<OpaqueElement> {
+        self.current_host
+    }
+
+    /// Runs F with a deeper nesting level, with the given element as the anchor,
+    /// for a :has(...) selector, for example.
+    #[inline]
+    pub fn nest_for_relative_selector<F, R>(&mut self, anchor: OpaqueElement, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        debug_assert!(
+            self.current_relative_selector_anchor.is_none(),
+            "Nesting should've been rejected at parse time"
+        );
+        self.current_relative_selector_anchor = Some(anchor);
+        let result = self.nest(f);
+        self.current_relative_selector_anchor = None;
+        result
+    }
+
+    /// Runs F with a deeper nesting level, with the given element as the scope.
+    #[inline]
+    pub fn nest_for_scope<F, R>(&mut self, scope: Option<OpaqueElement>, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        let original_scope_element = self.scope_element;
+        self.scope_element = scope;
+        let result = f(self);
+        self.scope_element = original_scope_element;
+        result
+    }
+
+    /// Runs F with a deeper nesting level, with the given element as the scope, for
+    /// matching `scope-start` and/or `scope-end` conditions.
+    #[inline]
+    pub fn nest_for_scope_condition<F, R>(&mut self, scope: Option<OpaqueElement>, f: F) -> R
+    where
+        F: FnOnce(&mut Self) -> R,
+    {
+        let original_matching_mode = self.matching_mode;
+        // We may as well be matching for a pseudo-element inside `@scope`, but
+        // the scope-defining selectors wouldn't be matching them.
+        self.matching_mode = MatchingMode::Normal;
+        let result = self.nest_for_scope(scope, f);
+        self.matching_mode = original_matching_mode;
+        result
+    }
+
+    /// Returns the current anchor element to evaluate the relative selector against.
+    #[inline]
+    pub fn relative_selector_anchor(&self) -> Option<OpaqueElement> {
+        self.current_relative_selector_anchor
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/kleene_value.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/kleene_value.rs
new file mode 100644
index 000000000000..96d6457e600a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/kleene_value.rs
@@ -0,0 +1,134 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Kleen logic: https://en.wikipedia.org/wiki/Three-valued_logic#Kleene_and_Priest_logics
+
+/// A "trilean" value based on Kleen logic.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum KleeneValue {
+    /// False
+    False = 0,
+    /// True
+    True = 1,
+    /// Either true or false, but we’re not sure which yet.
+    Unknown,
+}
+
+impl From<bool> for KleeneValue {
+    fn from(b: bool) -> Self {
+        if b {
+            Self::True
+        } else {
+            Self::False
+        }
+    }
+}
+
+impl KleeneValue {
+    /// Turns this Kleene value to a bool, taking the unknown value as an
+    /// argument.
+    pub fn to_bool(self, unknown: bool) -> bool {
+        match self {
+            Self::True => true,
+            Self::False => false,
+            Self::Unknown => unknown,
+        }
+    }
+
+    /// Return true if any result of f() is true. Otherwise, return the strongest value seen.
+    /// Returns false if empty, like that of `Iterator`.
+    #[inline(always)]
+    pub fn any<T>(
+        iter: impl Iterator<Item = T>,
+        f: impl FnMut(T) -> Self,
+    ) -> Self {
+        Self::any_value(iter, Self::True, Self::False, f)
+    }
+
+    /// Return false if any results of f() is false. Otherwise, return the strongest value seen.
+    /// Returns true if empty, opposite of `Iterator`.
+    #[inline(always)]
+    pub fn any_false<T>(
+        iter: impl Iterator<Item = T>,
+        f: impl FnMut(T) -> Self,
+    ) -> Self {
+        Self::any_value(iter, Self::False, Self::True, f)
+    }
+
+    #[inline(always)]
+    fn any_value<T>(
+        iter: impl Iterator<Item = T>,
+        value: Self,
+        on_empty: Self,
+        mut f: impl FnMut(T) -> Self,
+    ) -> Self {
+        let mut result = None;
+        for item in iter {
+            let r = f(item);
+            if r == value {
+                return r;
+            }
+            if let Some(v) = result.as_mut() {
+                *v = *v & r;
+            } else {
+                result = Some(r);
+            }
+        }
+        result.unwrap_or(on_empty)
+    }
+}
+
+impl std::ops::Not for KleeneValue {
+    type Output = Self;
+
+    fn not(self) -> Self {
+        match self {
+            Self::True => Self::False,
+            Self::False => Self::True,
+            Self::Unknown => Self::Unknown,
+        }
+    }
+}
+
+// Implements the logical and operation.
+impl std::ops::BitAnd for KleeneValue {
+    type Output = Self;
+
+    fn bitand(self, other: Self) -> Self {
+        if self == Self::False || other == Self::False {
+            return Self::False;
+        }
+        if self == Self::Unknown || other == Self::Unknown {
+            return Self::Unknown;
+        }
+        Self::True
+    }
+}
+
+// Implements the logical or operation.
+impl std::ops::BitOr for KleeneValue {
+    type Output = Self;
+
+    fn bitor(self, other: Self) -> Self {
+        if self == Self::True || other == Self::True {
+            return Self::True;
+        }
+        if self == Self::Unknown || other == Self::Unknown {
+            return Self::Unknown;
+        }
+        Self::False
+    }
+}
+
+impl std::ops::BitOrAssign for KleeneValue {
+    fn bitor_assign(&mut self, other: Self) {
+        *self = *self | other;
+    }
+}
+
+impl std::ops::BitAndAssign for KleeneValue {
+    fn bitand_assign(&mut self, other: Self) {
+        *self = *self & other;
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs
new file mode 100644
index 000000000000..e60fe5be257f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// Make |cargo bench| work.
+#![cfg_attr(feature = "bench", feature(test))]
+
+pub mod attr;
+pub mod bloom;
+mod builder;
+pub mod context;
+pub mod kleene_value;
+pub mod matching;
+mod nth_index_cache;
+pub mod parser;
+pub mod relative_selector;
+pub mod sink;
+mod tree;
+pub mod visitor;
+
+pub use crate::nth_index_cache::NthIndexCache;
+pub use crate::parser::{Parser, SelectorImpl, SelectorList};
+pub use crate::tree::{Element, OpaqueElement};
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/matching.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/matching.rs
new file mode 100644
index 000000000000..2d56e988579c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/matching.rs
@@ -0,0 +1,1516 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::attr::{
+    AttrSelectorOperation, AttrSelectorWithOptionalNamespace, CaseSensitivity, NamespaceConstraint,
+    ParsedAttrSelectorOperation, ParsedCaseSensitivity,
+};
+use crate::bloom::{BloomFilter, BLOOM_HASH_MASK};
+use crate::kleene_value::KleeneValue;
+use crate::parser::{
+    AncestorHashes, Combinator, Component, FeaturelessHostMatches, LocalName, NthSelectorData,
+    RelativeSelectorMatchHint,
+};
+use crate::parser::{
+    NonTSPseudoClass, RelativeSelector, Selector, SelectorImpl, SelectorIter, SelectorList,
+};
+use crate::relative_selector::cache::RelativeSelectorCachedMatch;
+use crate::tree::Element;
+use log::debug;
+use smallvec::SmallVec;
+use std::borrow::Borrow;
+use bitflags::bitflags;
+use debug_unreachable::debug_unreachable;
+
+pub use crate::context::*;
+
+// The bloom filter for descendant CSS selectors will have a <1% false
+// positive rate until it has this many selectors in it, then it will
+// rapidly increase.
+pub static RECOMMENDED_SELECTOR_BLOOM_FILTER_SIZE: usize = 4096;
+
+bitflags! {
+    /// Set of flags that are set on either the element or its parent (depending
+    /// on the flag) if the element could potentially match a selector.
+    #[derive(Clone, Copy)]
+    pub struct ElementSelectorFlags: usize {
+        /// When a child is added or removed from the parent, all the children
+        /// must be restyled, because they may match :nth-last-child,
+        /// :last-of-type, :nth-last-of-type, or :only-of-type.
+        const HAS_SLOW_SELECTOR = 1 << 0;
+
+        /// When a child is added or removed from the parent, any later
+        /// children must be restyled, because they may match :nth-child,
+        /// :first-of-type, or :nth-of-type.
+        const HAS_SLOW_SELECTOR_LATER_SIBLINGS = 1 << 1;
+
+        /// HAS_SLOW_SELECTOR* was set by the presence of :nth (But not of).
+        const HAS_SLOW_SELECTOR_NTH = 1 << 2;
+
+        /// When a DOM mutation occurs on a child that might be matched by
+        /// :nth-last-child(.. of <selector list>), earlier children must be
+        /// restyled, and HAS_SLOW_SELECTOR will be set (which normally
+        /// indicates that all children will be restyled).
+        ///
+        /// Similarly, when a DOM mutation occurs on a child that might be
+        /// matched by :nth-child(.. of <selector list>), later children must be
+        /// restyled, and HAS_SLOW_SELECTOR_LATER_SIBLINGS will be set.
+        const HAS_SLOW_SELECTOR_NTH_OF = 1 << 3;
+
+        /// When a child is added or removed from the parent, the first and
+        /// last children must be restyled, because they may match :first-child,
+        /// :last-child, or :only-child.
+        const HAS_EDGE_CHILD_SELECTOR = 1 << 4;
+
+        /// The element has an empty selector, so when a child is appended we
+        /// might need to restyle the parent completely.
+        const HAS_EMPTY_SELECTOR = 1 << 5;
+
+        /// The element may anchor a relative selector.
+        const ANCHORS_RELATIVE_SELECTOR = 1 << 6;
+
+        /// The element may anchor a relative selector that is not the subject
+        /// of the whole selector.
+        const ANCHORS_RELATIVE_SELECTOR_NON_SUBJECT = 1 << 7;
+
+        /// The element is reached by a relative selector search in the sibling direction.
+        const RELATIVE_SELECTOR_SEARCH_DIRECTION_SIBLING = 1 << 8;
+
+        /// The element is reached by a relative selector search in the ancestor direction.
+        const RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR = 1 << 9;
+
+        // The element is reached by a relative selector search in both sibling and ancestor directions.
+        const RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR_SIBLING =
+            Self::RELATIVE_SELECTOR_SEARCH_DIRECTION_SIBLING.bits() |
+            Self::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR.bits();
+    }
+}
+
+impl ElementSelectorFlags {
+    /// Returns the subset of flags that apply to the element.
+    pub fn for_self(self) -> ElementSelectorFlags {
+        self & (ElementSelectorFlags::HAS_EMPTY_SELECTOR |
+            ElementSelectorFlags::ANCHORS_RELATIVE_SELECTOR |
+            ElementSelectorFlags::ANCHORS_RELATIVE_SELECTOR_NON_SUBJECT |
+            ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_SIBLING |
+            ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR)
+    }
+
+    /// Returns the subset of flags that apply to the parent.
+    pub fn for_parent(self) -> ElementSelectorFlags {
+        self & (ElementSelectorFlags::HAS_SLOW_SELECTOR |
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS |
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_NTH |
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_NTH_OF |
+            ElementSelectorFlags::HAS_EDGE_CHILD_SELECTOR)
+    }
+}
+
+/// Holds per-compound-selector data.
+struct LocalMatchingContext<'a, 'b: 'a, Impl: SelectorImpl> {
+    shared: &'a mut MatchingContext<'b, Impl>,
+    rightmost: SubjectOrPseudoElement,
+    quirks_data: Option<SelectorIter<'a, Impl>>,
+}
+
+#[inline(always)]
+pub fn matches_selector_list<E>(
+    selector_list: &SelectorList<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+) -> bool
+where
+    E: Element,
+{
+    // This is pretty much any(..) but manually inlined because the compiler
+    // refuses to do so from querySelector / querySelectorAll.
+    for selector in selector_list.slice() {
+        let matches = matches_selector(selector, 0, None, element, context);
+        if matches {
+            return true;
+        }
+    }
+
+    false
+}
+
+/// Given the ancestor hashes from a selector, see if the current element,
+/// represented by the bloom filter, has a chance of matching at all.
+#[inline(always)]
+pub fn selector_may_match(hashes: &AncestorHashes, bf: &BloomFilter) -> bool {
+    // Check the first three hashes. Note that we can check for zero before
+    // masking off the high bits, since if any of the first three hashes is
+    // zero the fourth will be as well. We also take care to avoid the
+    // special-case complexity of the fourth hash until we actually reach it,
+    // because we usually don't.
+    //
+    // To be clear: this is all extremely hot.
+    for i in 0..3 {
+        let packed = hashes.packed_hashes[i];
+        if packed == 0 {
+            // No more hashes left - unable to fast-reject.
+            return true;
+        }
+
+        if !bf.might_contain_hash(packed & BLOOM_HASH_MASK) {
+            // Hooray! We fast-rejected on this hash.
+            return false;
+        }
+    }
+
+    // Now do the slighty-more-complex work of synthesizing the fourth hash,
+    // and check it against the filter if it exists.
+    let fourth = hashes.fourth_hash();
+    fourth == 0 || bf.might_contain_hash(fourth)
+}
+
+/// A result of selector matching, includes 3 failure types,
+///
+///   NotMatchedAndRestartFromClosestLaterSibling
+///   NotMatchedAndRestartFromClosestDescendant
+///   NotMatchedGlobally
+///
+/// When NotMatchedGlobally appears, stop selector matching completely since
+/// the succeeding selectors never matches.
+/// It is raised when
+///   Child combinator cannot find the candidate element.
+///   Descendant combinator cannot find the candidate element.
+///
+/// When NotMatchedAndRestartFromClosestDescendant appears, the selector
+/// matching does backtracking and restarts from the closest Descendant
+/// combinator.
+/// It is raised when
+///   NextSibling combinator cannot find the candidate element.
+///   LaterSibling combinator cannot find the candidate element.
+///   Child combinator doesn't match on the found element.
+///
+/// When NotMatchedAndRestartFromClosestLaterSibling appears, the selector
+/// matching does backtracking and restarts from the closest LaterSibling
+/// combinator.
+/// It is raised when
+///   NextSibling combinator doesn't match on the found element.
+///
+/// For example, when the selector "d1 d2 a" is provided and we cannot *find*
+/// an appropriate ancestor element for "d1", this selector matching raises
+/// NotMatchedGlobally since even if "d2" is moved to more upper element, the
+/// candidates for "d1" becomes less than before and d1 .
+///
+/// The next example is siblings. When the selector "b1 + b2 ~ d1 a" is
+/// provided and we cannot *find* an appropriate brother element for b1,
+/// the selector matching raises NotMatchedAndRestartFromClosestDescendant.
+/// The selectors ("b1 + b2 ~") doesn't match and matching restart from "d1".
+///
+/// The additional example is child and sibling. When the selector
+/// "b1 + c1 > b2 ~ d1 a" is provided and the selector "b1" doesn't match on
+/// the element, this "b1" raises NotMatchedAndRestartFromClosestLaterSibling.
+/// However since the selector "c1" raises
+/// NotMatchedAndRestartFromClosestDescendant. So the selector
+/// "b1 + c1 > b2 ~ " doesn't match and restart matching from "d1".
+///
+/// There is also the unknown result, which is used during invalidation when
+/// specific selector is being tested for before/after comparison. More specifically,
+/// selectors that are too expensive to correctly compute during invalidation may
+/// return unknown, as the computation will be thrown away and only to be recomputed
+/// during styling. For most cases, the unknown result can be treated as matching.
+/// This is because a compound of selectors acts like &&, and unknown && matched
+/// == matched and unknown && not-matched == not-matched. However, some selectors,
+/// like `:is()`, behave like || i.e. `:is(.a, .b)` == a || b. Treating unknown
+/// == matching then causes these selectors to always return matching, which undesired
+/// for before/after comparison. Coercing to not-matched doesn't work since each
+/// inner selector may have compounds: e.g. Toggling `.foo` in `:is(.foo:has(..))`
+/// with coersion to not-matched would result in an invalid before/after comparison
+/// of not-matched/not-matched.
+#[derive(Clone, Copy, Eq, PartialEq)]
+enum SelectorMatchingResult {
+    Matched,
+    NotMatchedAndRestartFromClosestLaterSibling,
+    NotMatchedAndRestartFromClosestDescendant,
+    NotMatchedGlobally,
+    Unknown,
+}
+
+impl From<SelectorMatchingResult> for KleeneValue {
+    fn from(value: SelectorMatchingResult) -> Self {
+        match value {
+            SelectorMatchingResult::Matched => KleeneValue::True,
+            SelectorMatchingResult::Unknown => KleeneValue::Unknown,
+            SelectorMatchingResult::NotMatchedAndRestartFromClosestLaterSibling |
+            SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant |
+            SelectorMatchingResult::NotMatchedGlobally => KleeneValue::False,
+        }
+    }
+}
+
+/// Matches a selector, fast-rejecting against a bloom filter.
+///
+/// We accept an offset to allow consumers to represent and match against
+/// partial selectors (indexed from the right). We use this API design, rather
+/// than having the callers pass a SelectorIter, because creating a SelectorIter
+/// requires dereferencing the selector to get the length, which adds an
+/// unncessary cache miss for cases when we can fast-reject with AncestorHashes
+/// (which the caller can store inline with the selector pointer).
+#[inline(always)]
+pub fn matches_selector<E>(
+    selector: &Selector<E::Impl>,
+    offset: usize,
+    hashes: Option<&AncestorHashes>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+) -> bool
+where
+    E: Element,
+{
+    let result = matches_selector_kleene(selector, offset, hashes, element, context);
+    if cfg!(debug_assertions) && result == KleeneValue::Unknown {
+        debug_assert!(
+            context.matching_for_invalidation_comparison().unwrap_or(false),
+            "How did we return unknown?"
+        );
+    }
+    result.to_bool(true)
+}
+
+/// Same as matches_selector, but returns the Kleene value as-is.
+#[inline(always)]
+pub fn matches_selector_kleene<E>(
+    selector: &Selector<E::Impl>,
+    offset: usize,
+    hashes: Option<&AncestorHashes>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+) -> KleeneValue
+where
+    E: Element,
+{
+    // Use the bloom filter to fast-reject.
+    if let Some(hashes) = hashes {
+        if let Some(filter) = context.bloom_filter {
+            if !selector_may_match(hashes, filter) {
+                return KleeneValue::False;
+            }
+        }
+    }
+    matches_complex_selector(
+        selector.iter_from(offset),
+        element,
+        context,
+        if selector.is_rightmost(offset) {
+            SubjectOrPseudoElement::Yes
+        } else {
+            SubjectOrPseudoElement::No
+        },
+    )
+}
+
+/// Whether a compound selector matched, and whether it was the rightmost
+/// selector inside the complex selector.
+pub enum CompoundSelectorMatchingResult {
+    /// The selector was fully matched.
+    FullyMatched,
+    /// The compound selector matched, and the next combinator offset is
+    /// `next_combinator_offset`.
+    Matched { next_combinator_offset: usize },
+    /// The selector didn't match.
+    NotMatched,
+}
+
+/// Matches a compound selector belonging to `selector`, starting at offset
+/// `from_offset`, matching left to right.
+///
+/// Requires that `from_offset` points to a `Combinator`.
+///
+/// NOTE(emilio): This doesn't allow to match in the leftmost sequence of the
+/// complex selector, but it happens to be the case we don't need it.
+pub fn matches_compound_selector_from<E>(
+    selector: &Selector<E::Impl>,
+    mut from_offset: usize,
+    context: &mut MatchingContext<E::Impl>,
+    element: &E,
+) -> CompoundSelectorMatchingResult
+where
+    E: Element,
+{
+    debug_assert!(
+        !context
+            .matching_for_invalidation_comparison()
+            .unwrap_or(false),
+        "CompoundSelectorMatchingResult doesn't support unknown"
+    );
+    if cfg!(debug_assertions) && from_offset != 0 {
+        selector.combinator_at_parse_order(from_offset - 1); // This asserts.
+    }
+
+    let mut local_context = LocalMatchingContext {
+        shared: context,
+        // We have no info if this is an outer selector. This function is called in
+        // an invalidation context, which only calls this for non-subject (i.e.
+        // Non-rightmost) positions.
+        rightmost: SubjectOrPseudoElement::No,
+        quirks_data: None,
+    };
+
+    // Find the end of the selector or the next combinator, then match
+    // backwards, so that we match in the same order as
+    // matches_complex_selector, which is usually faster.
+    let start_offset = from_offset;
+    for component in selector.iter_raw_parse_order_from(from_offset) {
+        if matches!(*component, Component::Combinator(..)) {
+            debug_assert_ne!(from_offset, 0, "Selector started with a combinator?");
+            break;
+        }
+
+        from_offset += 1;
+    }
+
+    debug_assert!(from_offset >= 1);
+    debug_assert!(from_offset <= selector.len());
+
+    let iter = selector.iter_from(selector.len() - from_offset);
+    debug_assert!(
+        iter.clone().next().is_some() || from_offset != selector.len(),
+        "Got the math wrong: {:?} | {:?} | {} {}",
+        selector,
+        selector.iter_raw_match_order().as_slice(),
+        from_offset,
+        start_offset
+    );
+
+    for component in iter {
+        let result = matches_simple_selector(component, element, &mut local_context);
+        debug_assert!(result != KleeneValue::Unknown, "Returned unknown in non invalidation context?");
+        if !result.to_bool(true) {
+            return CompoundSelectorMatchingResult::NotMatched;
+        }
+    }
+
+    if from_offset != selector.len() {
+        return CompoundSelectorMatchingResult::Matched {
+            next_combinator_offset: from_offset,
+        };
+    }
+
+    CompoundSelectorMatchingResult::FullyMatched
+}
+
+/// Matches a complex selector.
+#[inline(always)]
+fn matches_complex_selector<E>(
+    mut iter: SelectorIter<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue
+where
+    E: Element,
+{
+    // If this is the special pseudo-element mode, consume the ::pseudo-element
+    // before proceeding, since the caller has already handled that part.
+    if context.matching_mode() == MatchingMode::ForStatelessPseudoElement && !context.is_nested() {
+        // Consume the pseudo.
+        match *iter.next().unwrap() {
+            Component::PseudoElement(ref pseudo) => {
+                if let Some(ref f) = context.pseudo_element_matching_fn {
+                    if !f(pseudo) {
+                        return KleeneValue::False;
+                    }
+                }
+            },
+            ref other => {
+                debug_assert!(
+                    false,
+                    "Used MatchingMode::ForStatelessPseudoElement \
+                     in a non-pseudo selector {:?}",
+                    other
+                );
+                return KleeneValue::False;
+            },
+        }
+
+        if !iter.matches_for_stateless_pseudo_element() {
+            return KleeneValue::False;
+        }
+
+        // Advance to the non-pseudo-element part of the selector.
+        let next_sequence = iter.next_sequence().unwrap();
+        debug_assert_eq!(next_sequence, Combinator::PseudoElement);
+    }
+
+    matches_complex_selector_internal(
+        iter,
+        element,
+        context,
+        rightmost,
+        SubjectOrPseudoElement::Yes,
+    )
+    .into()
+}
+
+/// Matches each selector of a list as a complex selector
+fn matches_complex_selector_list<E: Element>(
+    list: &[Selector<E::Impl>],
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue {
+    KleeneValue::any(
+        list.iter(),
+        |selector| matches_complex_selector(
+            selector.iter(),
+            element,
+            context,
+            rightmost
+        )
+    )
+}
+
+fn matches_relative_selector<E: Element>(
+    relative_selector: &RelativeSelector<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> bool {
+    // Overall, we want to mark the path that we've traversed so that when an element
+    // is invalidated, we early-reject unnecessary relative selector invalidations.
+    if relative_selector.match_hint.is_descendant_direction() {
+        if context.needs_selector_flags() {
+            element.apply_selector_flags(
+                ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR,
+            );
+        }
+        let mut next_element = element.first_element_child();
+        while let Some(el) = next_element {
+            if context.needs_selector_flags() {
+                el.apply_selector_flags(
+                    ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR,
+                );
+            }
+            let mut matched = matches_complex_selector(
+                relative_selector.selector.iter(),
+                &el,
+                context,
+                rightmost,
+            )
+            .to_bool(true);
+            if !matched && relative_selector.match_hint.is_subtree() {
+                matched = matches_relative_selector_subtree(
+                    &relative_selector.selector,
+                    &el,
+                    context,
+                    rightmost,
+                );
+            }
+            if matched {
+                return true;
+            }
+            next_element = el.next_sibling_element();
+        }
+    } else {
+        debug_assert!(
+            matches!(
+                relative_selector.match_hint,
+                RelativeSelectorMatchHint::InNextSibling |
+                    RelativeSelectorMatchHint::InNextSiblingSubtree |
+                    RelativeSelectorMatchHint::InSibling |
+                    RelativeSelectorMatchHint::InSiblingSubtree
+            ),
+            "Not descendant direction, but also not sibling direction?"
+        );
+        if context.needs_selector_flags() {
+            element.apply_selector_flags(
+                ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_SIBLING,
+            );
+        }
+        let sibling_flag = if relative_selector.match_hint.is_subtree() {
+            ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR_SIBLING
+        } else {
+            ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_SIBLING
+        };
+        let mut next_element = element.next_sibling_element();
+        while let Some(el) = next_element {
+            if context.needs_selector_flags() {
+                el.apply_selector_flags(sibling_flag);
+            }
+            let matched = if relative_selector.match_hint.is_subtree() {
+                matches_relative_selector_subtree(
+                    &relative_selector.selector,
+                    &el,
+                    context,
+                    rightmost,
+                )
+            } else {
+                matches_complex_selector(relative_selector.selector.iter(), &el, context, rightmost)
+                    .to_bool(true)
+            };
+            if matched {
+                return true;
+            }
+            if relative_selector.match_hint.is_next_sibling() {
+                break;
+            }
+            next_element = el.next_sibling_element();
+        }
+    }
+    return false;
+}
+
+fn relative_selector_match_early<E: Element>(
+    selector: &RelativeSelector<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+) -> Option<bool> {
+    // See if we can return a cached result.
+    if let Some(cached) = context
+        .selector_caches
+        .relative_selector
+        .lookup(element.opaque(), selector)
+    {
+        return Some(cached.matched());
+    }
+    // See if we can fast-reject.
+    if context
+        .selector_caches
+        .relative_selector_filter_map
+        .fast_reject(element, selector, context.quirks_mode())
+    {
+        // Alright, add as unmatched to cache.
+        context.selector_caches.relative_selector.add(
+            element.opaque(),
+            selector,
+            RelativeSelectorCachedMatch::NotMatched,
+        );
+        return Some(false);
+    }
+    None
+}
+
+fn match_relative_selectors<E: Element>(
+    selectors: &[RelativeSelector<E::Impl>],
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue {
+    if context.relative_selector_anchor().is_some() {
+        // FIXME(emilio): This currently can happen with nesting, and it's not fully
+        // correct, arguably. But the ideal solution isn't super-clear either. For now,
+        // cope with it and explicitly reject it at match time. See [1] for discussion.
+        //
+        // [1]: https://github.com/w3c/csswg-drafts/issues/9600
+        return KleeneValue::False;
+    }
+    if let Some(may_return_unknown) = context.matching_for_invalidation_comparison() {
+        // In the context of invalidation, :has is expensive, especially because we
+        // can't use caching/filtering due to now/then matches. DOM structure also
+        // may have changed.
+        return if may_return_unknown {
+            KleeneValue::Unknown
+        } else {
+            KleeneValue::from(!context.in_negation())
+        };
+    }
+    context.nest_for_relative_selector(element.opaque(), |context| {
+        do_match_relative_selectors(selectors, element, context, rightmost)
+    }).into()
+}
+
+/// Matches a relative selector in a list of relative selectors.
+fn do_match_relative_selectors<E: Element>(
+    selectors: &[RelativeSelector<E::Impl>],
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> bool {
+    // Due to style sharing implications (See style sharing code), we mark the current styling context
+    // to mark elements considered for :has matching. Additionally, we want to mark the elements themselves,
+    // since we don't want to indiscriminately invalidate every element as a potential anchor.
+    if rightmost == SubjectOrPseudoElement::Yes {
+        if context.needs_selector_flags() {
+            element.apply_selector_flags(ElementSelectorFlags::ANCHORS_RELATIVE_SELECTOR);
+        }
+    } else {
+        if context.needs_selector_flags() {
+            element
+                .apply_selector_flags(ElementSelectorFlags::ANCHORS_RELATIVE_SELECTOR_NON_SUBJECT);
+        }
+    }
+
+    for relative_selector in selectors.iter() {
+        if let Some(result) = relative_selector_match_early(relative_selector, element, context) {
+            if result {
+                return true;
+            }
+            // Early return indicates no match, continue to next selector.
+            continue;
+        }
+
+        let matched = matches_relative_selector(relative_selector, element, context, rightmost);
+        context.selector_caches.relative_selector.add(
+            element.opaque(),
+            relative_selector,
+            if matched {
+                RelativeSelectorCachedMatch::Matched
+            } else {
+                RelativeSelectorCachedMatch::NotMatched
+            },
+        );
+        if matched {
+            return true;
+        }
+    }
+
+    false
+}
+
+fn matches_relative_selector_subtree<E: Element>(
+    selector: &Selector<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> bool {
+    let mut current = element.first_element_child();
+
+    while let Some(el) = current {
+        if context.needs_selector_flags() {
+            el.apply_selector_flags(
+                ElementSelectorFlags::RELATIVE_SELECTOR_SEARCH_DIRECTION_ANCESTOR,
+            );
+        }
+        if matches_complex_selector(selector.iter(), &el, context, rightmost).to_bool(true) {
+            return true;
+        }
+
+        if matches_relative_selector_subtree(selector, &el, context, rightmost) {
+            return true;
+        }
+
+        current = el.next_sibling_element();
+    }
+
+    false
+}
+
+/// Whether the :hover and :active quirk applies.
+///
+/// https://quirks.spec.whatwg.org/#the-active-and-hover-quirk
+fn hover_and_active_quirk_applies<Impl: SelectorImpl>(
+    selector_iter: &SelectorIter<Impl>,
+    context: &MatchingContext<Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> bool {
+    if context.quirks_mode() != QuirksMode::Quirks {
+        return false;
+    }
+
+    if context.is_nested() {
+        return false;
+    }
+
+    // This compound selector had a pseudo-element to the right that we
+    // intentionally skipped.
+    if rightmost == SubjectOrPseudoElement::Yes &&
+        context.matching_mode() == MatchingMode::ForStatelessPseudoElement
+    {
+        return false;
+    }
+
+    selector_iter.clone().all(|simple| match *simple {
+        Component::NonTSPseudoClass(ref pseudo_class) => pseudo_class.is_active_or_hover(),
+        _ => false,
+    })
+}
+
+#[derive(Clone, Copy, PartialEq)]
+enum SubjectOrPseudoElement {
+    Yes,
+    No,
+}
+
+fn host_for_part<E>(element: &E, context: &MatchingContext<E::Impl>) -> Option<E>
+where
+    E: Element,
+{
+    let scope = context.current_host;
+    let mut curr = element.containing_shadow_host()?;
+    if scope == Some(curr.opaque()) {
+        return Some(curr);
+    }
+    loop {
+        let parent = curr.containing_shadow_host();
+        if parent.as_ref().map(|h| h.opaque()) == scope {
+            return Some(curr);
+        }
+        curr = parent?;
+    }
+}
+
+fn assigned_slot<E>(element: &E, context: &MatchingContext<E::Impl>) -> Option<E>
+where
+    E: Element,
+{
+    debug_assert!(element
+        .assigned_slot()
+        .map_or(true, |s| s.is_html_slot_element()));
+    let scope = context.current_host?;
+    let mut current_slot = element.assigned_slot()?;
+    while current_slot.containing_shadow_host().unwrap().opaque() != scope {
+        current_slot = current_slot.assigned_slot()?;
+    }
+    Some(current_slot)
+}
+
+#[inline(always)]
+fn next_element_for_combinator<E>(
+    element: &E,
+    combinator: Combinator,
+    selector: &SelectorIter<E::Impl>,
+    context: &MatchingContext<E::Impl>,
+) -> Option<E>
+where
+    E: Element,
+{
+    match combinator {
+        Combinator::NextSibling | Combinator::LaterSibling => element.prev_sibling_element(),
+        Combinator::Child | Combinator::Descendant => {
+            match element.parent_element() {
+                Some(e) => return Some(e),
+                None => {},
+            }
+
+            if !element.parent_node_is_shadow_root() {
+                return None;
+            }
+
+            // https://drafts.csswg.org/css-scoping/#host-element-in-tree:
+            //
+            //   For the purpose of Selectors, a shadow host also appears in
+            //   its shadow tree, with the contents of the shadow tree treated
+            //   as its children. (In other words, the shadow host is treated as
+            //   replacing the shadow root node.)
+            //
+            // and also:
+            //
+            //   When considered within its own shadow trees, the shadow host is
+            //   featureless. Only the :host, :host(), and :host-context()
+            //   pseudo-classes are allowed to match it.
+            //
+            // Since we know that the parent is a shadow root, we necessarily
+            // are in a shadow tree of the host, and the next selector will only
+            // match if the selector is a featureless :host selector.
+            let matches_featureless_host = selector.clone().is_featureless_host_selector();
+            if matches_featureless_host.intersects(FeaturelessHostMatches::FOR_HOST) {
+                // May not match the inner selector, but we can't really call that here.
+                return element.containing_shadow_host()
+            } else if matches_featureless_host.intersects(FeaturelessHostMatches::FOR_SCOPE) {
+                let host = element.containing_shadow_host();
+                // If this element's shadow host matches the `:scope` element, we should
+                // treat the `:scope` selector as featureless.
+                // See https://github.com/w3c/csswg-drafts/issues/9025.
+                if context.scope_element.is_some() &&
+                    context.scope_element.clone() == host.clone().map(|e| e.opaque())
+                {
+                    return host;
+                }
+                return None;
+            } else {
+                return None;
+            }
+        },
+        Combinator::Part => host_for_part(element, context),
+        Combinator::SlotAssignment => assigned_slot(element, context),
+        Combinator::PseudoElement => element.pseudo_element_originating_element(),
+    }
+}
+
+fn matches_complex_selector_internal<E>(
+    mut selector_iter: SelectorIter<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+    first_subject_compound: SubjectOrPseudoElement,
+) -> SelectorMatchingResult
+where
+    E: Element,
+{
+    debug!(
+        "Matching complex selector {:?} for {:?}",
+        selector_iter, element
+    );
+
+    let matches_compound_selector = {
+        let result = matches_compound_selector(&mut selector_iter, element, context, rightmost);
+        // We only care for unknown match in the first subject in compound - in the context of comparison
+        // invalidation, ancestors/previous sibling being an unknown match doesn't matter - we must
+        // invalidate to guarantee correctness.
+        if result == KleeneValue::Unknown && first_subject_compound == SubjectOrPseudoElement::No {
+            debug_assert!(
+                context
+                    .matching_for_invalidation_comparison()
+                    .unwrap_or(false),
+                "How did we return unknown?"
+            );
+            // Coerce the result to matched.
+            KleeneValue::True
+        } else {
+            result
+        }
+    };
+
+    let combinator = selector_iter.next_sequence();
+    if combinator.map_or(false, |c| c.is_sibling()) {
+        if context.needs_selector_flags() {
+            element.apply_selector_flags(ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS);
+        }
+    }
+
+    // We don't short circuit unknown here, since the rest of the selector
+    // to the left of this compound may return false.
+    if matches_compound_selector == KleeneValue::False {
+        return SelectorMatchingResult::NotMatchedAndRestartFromClosestLaterSibling;
+    }
+
+    let combinator = match combinator {
+        None => {
+            return match matches_compound_selector {
+                KleeneValue::True => SelectorMatchingResult::Matched,
+                KleeneValue::Unknown => SelectorMatchingResult::Unknown,
+                KleeneValue::False => unreachable!(),
+            }
+        },
+        Some(c) => c,
+    };
+
+    let (candidate_not_found, rightmost, first_subject_compound) = match combinator {
+        Combinator::NextSibling | Combinator::LaterSibling => (
+            SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant,
+            SubjectOrPseudoElement::No,
+            SubjectOrPseudoElement::No,
+        ),
+        Combinator::Child |
+        Combinator::Descendant |
+        Combinator::SlotAssignment |
+        Combinator::Part => (
+            SelectorMatchingResult::NotMatchedGlobally,
+            SubjectOrPseudoElement::No,
+            SubjectOrPseudoElement::No,
+        ),
+        Combinator::PseudoElement => (
+            SelectorMatchingResult::NotMatchedGlobally,
+            rightmost,
+            first_subject_compound,
+        ),
+    };
+
+    // Stop matching :visited as soon as we find a link, or a combinator for
+    // something that isn't an ancestor.
+    let mut visited_handling = if combinator.is_sibling() {
+        VisitedHandlingMode::AllLinksUnvisited
+    } else {
+        context.visited_handling()
+    };
+
+    let mut element = element.clone();
+    loop {
+        if element.is_link() {
+            visited_handling = VisitedHandlingMode::AllLinksUnvisited;
+        }
+
+        element = match next_element_for_combinator(&element, combinator, &selector_iter, &context)
+        {
+            None => return candidate_not_found,
+            Some(next_element) => next_element,
+        };
+
+        let result = context.with_visited_handling_mode(visited_handling, |context| {
+            matches_complex_selector_internal(
+                selector_iter.clone(),
+                &element,
+                context,
+                rightmost,
+                first_subject_compound,
+            )
+        });
+
+        match (result, combinator) {
+            // Return the status immediately.
+            (SelectorMatchingResult::Matched | SelectorMatchingResult::Unknown, _) => {
+                debug_assert!(
+                    matches_compound_selector.to_bool(true),
+                    "Compound didn't match?"
+                );
+                if result == SelectorMatchingResult::Matched &&
+                    matches_compound_selector.to_bool(false)
+                {
+                    // Matches without question
+                    return result;
+                }
+                // Something returned unknown, so return unknown.
+                return SelectorMatchingResult::Unknown;
+            },
+            (SelectorMatchingResult::NotMatchedGlobally, _) | (_, Combinator::NextSibling) => {
+                return result;
+            },
+
+            // Upgrade the failure status to
+            // NotMatchedAndRestartFromClosestDescendant.
+            (_, Combinator::PseudoElement) | (_, Combinator::Child) => {
+                return SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant;
+            },
+
+            // If the failure status is
+            // NotMatchedAndRestartFromClosestDescendant and combinator is
+            // Combinator::LaterSibling, give up this Combinator::LaterSibling
+            // matching and restart from the closest descendant combinator.
+            (
+                SelectorMatchingResult::NotMatchedAndRestartFromClosestDescendant,
+                Combinator::LaterSibling,
+            ) => {
+                return result;
+            },
+
+            // The Combinator::Descendant combinator and the status is
+            // NotMatchedAndRestartFromClosestLaterSibling or
+            // NotMatchedAndRestartFromClosestDescendant, or the
+            // Combinator::LaterSibling combinator and the status is
+            // NotMatchedAndRestartFromClosestDescendant, we can continue to
+            // matching on the next candidate element.
+            _ => {},
+        }
+    }
+}
+
+#[inline]
+fn matches_local_name<E>(element: &E, local_name: &LocalName<E::Impl>) -> bool
+where
+    E: Element,
+{
+    let name = select_name(element, &local_name.name, &local_name.lower_name).borrow();
+    element.has_local_name(name)
+}
+
+fn matches_part<E>(
+    element: &E,
+    parts: &[<E::Impl as SelectorImpl>::Identifier],
+    context: &mut MatchingContext<E::Impl>,
+) -> bool
+where
+    E: Element,
+{
+    let mut hosts = SmallVec::<[E; 4]>::new();
+
+    let mut host = match element.containing_shadow_host() {
+        Some(h) => h,
+        None => return false,
+    };
+
+    let current_host = context.current_host;
+    if current_host != Some(host.opaque()) {
+        loop {
+            let outer_host = host.containing_shadow_host();
+            if outer_host.as_ref().map(|h| h.opaque()) == current_host {
+                break;
+            }
+            let outer_host = match outer_host {
+                Some(h) => h,
+                None => return false,
+            };
+            // TODO(emilio): if worth it, we could early return if
+            // host doesn't have the exportparts attribute.
+            hosts.push(host);
+            host = outer_host;
+        }
+    }
+
+    // Translate the part into the right scope.
+    parts.iter().all(|part| {
+        let mut part = part.clone();
+        for host in hosts.iter().rev() {
+            part = match host.imported_part(&part) {
+                Some(p) => p,
+                None => return false,
+            };
+        }
+        element.is_part(&part)
+    })
+}
+
+fn matches_host<E>(
+    element: &E,
+    selector: Option<&Selector<E::Impl>>,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue
+where
+    E: Element,
+{
+    let host = match context.shadow_host() {
+        Some(h) => h,
+        None => return KleeneValue::False,
+    };
+    if host != element.opaque() {
+        return KleeneValue::False;
+    }
+    selector.map_or(KleeneValue::True, |selector| {
+        context
+            .nest(|context| matches_complex_selector(selector.iter(), element, context, rightmost))
+    })
+}
+
+fn matches_slotted<E>(
+    element: &E,
+    selector: &Selector<E::Impl>,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue
+where
+    E: Element,
+{
+    // <slots> are never flattened tree slottables.
+    if element.is_html_slot_element() {
+        return KleeneValue::False;
+    }
+    context.nest(|context| matches_complex_selector(selector.iter(), element, context, rightmost))
+}
+
+fn matches_rare_attribute_selector<E>(
+    element: &E,
+    attr_sel: &AttrSelectorWithOptionalNamespace<E::Impl>,
+) -> bool
+where
+    E: Element,
+{
+    let empty_string;
+    let namespace = match attr_sel.namespace() {
+        Some(ns) => ns,
+        None => {
+            empty_string = crate::parser::namespace_empty_string::<E::Impl>();
+            NamespaceConstraint::Specific(&empty_string)
+        },
+    };
+    element.attr_matches(
+        &namespace,
+        select_name(element, &attr_sel.local_name, &attr_sel.local_name_lower),
+        &match attr_sel.operation {
+            ParsedAttrSelectorOperation::Exists => AttrSelectorOperation::Exists,
+            ParsedAttrSelectorOperation::WithValue {
+                operator,
+                case_sensitivity,
+                ref value,
+            } => AttrSelectorOperation::WithValue {
+                operator,
+                case_sensitivity: to_unconditional_case_sensitivity(case_sensitivity, element),
+                value,
+            },
+        },
+    )
+}
+
+/// Determines whether the given element matches the given compound selector.
+#[inline]
+fn matches_compound_selector<E>(
+    selector_iter: &mut SelectorIter<E::Impl>,
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue
+where
+    E: Element,
+{
+    let quirks_data = if context.quirks_mode() == QuirksMode::Quirks {
+        Some(selector_iter.clone())
+    } else {
+        None
+    };
+    let mut local_context = LocalMatchingContext {
+        shared: context,
+        rightmost,
+        quirks_data,
+    };
+    KleeneValue::any_false(
+        selector_iter,
+        |simple| matches_simple_selector(
+            simple,
+            element,
+            &mut local_context
+        )
+    )
+}
+
+/// Determines whether the given element matches the given single selector.
+fn matches_simple_selector<E>(
+    selector: &Component<E::Impl>,
+    element: &E,
+    context: &mut LocalMatchingContext<E::Impl>,
+) -> KleeneValue
+where
+    E: Element,
+{
+    debug_assert!(context.shared.is_nested() || !context.shared.in_negation());
+    let rightmost = context.rightmost;
+    KleeneValue::from(match *selector {
+        Component::ID(ref id) => {
+            element.has_id(id, context.shared.classes_and_ids_case_sensitivity())
+        },
+        Component::Class(ref class) => {
+            element.has_class(class, context.shared.classes_and_ids_case_sensitivity())
+        },
+        Component::LocalName(ref local_name) => matches_local_name(element, local_name),
+        Component::AttributeInNoNamespaceExists {
+            ref local_name,
+            ref local_name_lower,
+        } => element.has_attr_in_no_namespace(select_name(element, local_name, local_name_lower)),
+        Component::AttributeInNoNamespace {
+            ref local_name,
+            ref value,
+            operator,
+            case_sensitivity,
+        } => element.attr_matches(
+            &NamespaceConstraint::Specific(&crate::parser::namespace_empty_string::<E::Impl>()),
+            local_name,
+            &AttrSelectorOperation::WithValue {
+                operator,
+                case_sensitivity: to_unconditional_case_sensitivity(case_sensitivity, element),
+                value,
+            },
+        ),
+        Component::AttributeOther(ref attr_sel) => {
+            matches_rare_attribute_selector(element, attr_sel)
+        },
+        Component::Part(ref parts) => matches_part(element, parts, &mut context.shared),
+        Component::Slotted(ref selector) => {
+            return matches_slotted(element, selector, &mut context.shared, rightmost);
+        },
+        Component::PseudoElement(ref pseudo) => {
+            element.match_pseudo_element(pseudo, context.shared)
+        },
+        Component::ExplicitUniversalType | Component::ExplicitAnyNamespace => true,
+        Component::Namespace(_, ref url) | Component::DefaultNamespace(ref url) => {
+            element.has_namespace(&url.borrow())
+        },
+        Component::ExplicitNoNamespace => {
+            let ns = crate::parser::namespace_empty_string::<E::Impl>();
+            element.has_namespace(&ns.borrow())
+        },
+        Component::NonTSPseudoClass(ref pc) => {
+            if let Some(ref iter) = context.quirks_data {
+                if pc.is_active_or_hover() &&
+                    !element.is_link() &&
+                    hover_and_active_quirk_applies(iter, context.shared, context.rightmost)
+                {
+                    return KleeneValue::False;
+                }
+            }
+            element.match_non_ts_pseudo_class(pc, &mut context.shared)
+        },
+        Component::Root => element.is_root(),
+        Component::Empty => {
+            if context.shared.needs_selector_flags() {
+                element.apply_selector_flags(ElementSelectorFlags::HAS_EMPTY_SELECTOR);
+            }
+            element.is_empty()
+        },
+        Component::Host(ref selector) => {
+            return matches_host(element, selector.as_ref(), &mut context.shared, rightmost);
+        },
+        Component::ParentSelector | Component::Scope | Component::ImplicitScope => match context.shared.scope_element {
+            Some(ref scope_element) => element.opaque() == *scope_element,
+            None => element.is_root(),
+        },
+        Component::Nth(ref nth_data) => {
+            return matches_generic_nth_child(element, context.shared, nth_data, &[], rightmost);
+        },
+        Component::NthOf(ref nth_of_data) => {
+            return context.shared.nest(|context| {
+                matches_generic_nth_child(
+                    element,
+                    context,
+                    nth_of_data.nth_data(),
+                    nth_of_data.selectors(),
+                    rightmost,
+                )
+            })
+        },
+        Component::Is(ref list) | Component::Where(ref list) => {
+            return context.shared.nest(|context| {
+                matches_complex_selector_list(list.slice(), element, context, rightmost)
+            })
+        },
+        Component::Negation(ref list) => {
+            return context.shared.nest_for_negation(|context| {
+                !matches_complex_selector_list(list.slice(), element, context, rightmost)
+            })
+        },
+        Component::Has(ref relative_selectors) => {
+            return match_relative_selectors(
+                relative_selectors,
+                element,
+                context.shared,
+                rightmost,
+            );
+        },
+        Component::Combinator(_) => unsafe {
+            debug_unreachable!("Shouldn't try to selector-match combinators")
+        },
+        Component::RelativeSelectorAnchor => {
+            let anchor = context.shared.relative_selector_anchor();
+            // We may match inner relative selectors, in which case we want to always match.
+            anchor.map_or(true, |a| a == element.opaque())
+        },
+        Component::Invalid(..) => false,
+    })
+}
+
+#[inline(always)]
+pub fn select_name<'a, E: Element, T: PartialEq>(
+    element: &E,
+    local_name: &'a T,
+    local_name_lower: &'a T,
+) -> &'a T {
+    if local_name == local_name_lower || element.is_html_element_in_html_document() {
+        local_name_lower
+    } else {
+        local_name
+    }
+}
+
+#[inline(always)]
+pub fn to_unconditional_case_sensitivity<'a, E: Element>(
+    parsed: ParsedCaseSensitivity,
+    element: &E,
+) -> CaseSensitivity {
+    match parsed {
+        ParsedCaseSensitivity::CaseSensitive | ParsedCaseSensitivity::ExplicitCaseSensitive => {
+            CaseSensitivity::CaseSensitive
+        },
+        ParsedCaseSensitivity::AsciiCaseInsensitive => CaseSensitivity::AsciiCaseInsensitive,
+        ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {
+            if element.is_html_element_in_html_document() {
+                CaseSensitivity::AsciiCaseInsensitive
+            } else {
+                CaseSensitivity::CaseSensitive
+            }
+        },
+    }
+}
+
+fn matches_generic_nth_child<E>(
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    nth_data: &NthSelectorData,
+    selectors: &[Selector<E::Impl>],
+    rightmost: SubjectOrPseudoElement,
+) -> KleeneValue
+where
+    E: Element,
+{
+    if element.ignores_nth_child_selectors() {
+        return KleeneValue::False;
+    }
+    let has_selectors = !selectors.is_empty();
+    let selectors_match = !has_selectors ||
+        matches_complex_selector_list(selectors, element, context, rightmost).to_bool(true);
+    if let Some(may_return_unknown) = context.matching_for_invalidation_comparison() {
+        // Skip expensive indexing math in invalidation.
+        return if selectors_match && may_return_unknown {
+            KleeneValue::Unknown
+        } else {
+            KleeneValue::from(selectors_match && !context.in_negation())
+        };
+    }
+
+    let NthSelectorData { ty, a, b, .. } = *nth_data;
+    let is_of_type = ty.is_of_type();
+    if ty.is_only() {
+        debug_assert!(
+            !has_selectors,
+            ":only-child and :only-of-type cannot have a selector list!"
+        );
+        return KleeneValue::from(
+            matches_generic_nth_child(
+                element,
+                context,
+                &NthSelectorData::first(is_of_type),
+                selectors,
+                rightmost,
+            )
+            .to_bool(true) &&
+                matches_generic_nth_child(
+                    element,
+                    context,
+                    &NthSelectorData::last(is_of_type),
+                    selectors,
+                    rightmost,
+                )
+                .to_bool(true),
+        );
+    }
+
+    let is_from_end = ty.is_from_end();
+
+    // It's useful to know whether this can only select the first/last element
+    // child for optimization purposes, see the `HAS_EDGE_CHILD_SELECTOR` flag.
+    let is_edge_child_selector = nth_data.is_simple_edge() && !has_selectors;
+
+    if context.needs_selector_flags() {
+        let mut flags = if is_edge_child_selector {
+            ElementSelectorFlags::HAS_EDGE_CHILD_SELECTOR
+        } else if is_from_end {
+            ElementSelectorFlags::HAS_SLOW_SELECTOR
+        } else {
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_LATER_SIBLINGS
+        };
+        flags |= if has_selectors {
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_NTH_OF
+        } else {
+            ElementSelectorFlags::HAS_SLOW_SELECTOR_NTH
+        };
+        element.apply_selector_flags(flags);
+    }
+
+    if !selectors_match {
+        return KleeneValue::False;
+    }
+
+    // :first/last-child are rather trivial to match, don't bother with the
+    // cache.
+    if is_edge_child_selector {
+        return if is_from_end {
+            element.next_sibling_element()
+        } else {
+            element.prev_sibling_element()
+        }
+        .is_none()
+        .into();
+    }
+
+    // Lookup or compute the index.
+    let index = if let Some(i) = context
+        .nth_index_cache(is_of_type, is_from_end, selectors)
+        .lookup(element.opaque())
+    {
+        i
+    } else {
+        let i = nth_child_index(
+            element,
+            context,
+            selectors,
+            is_of_type,
+            is_from_end,
+            /* check_cache = */ true,
+            rightmost,
+        );
+        context
+            .nth_index_cache(is_of_type, is_from_end, selectors)
+            .insert(element.opaque(), i);
+        i
+    };
+    debug_assert_eq!(
+        index,
+        nth_child_index(
+            element,
+            context,
+            selectors,
+            is_of_type,
+            is_from_end,
+            /* check_cache = */ false,
+            rightmost,
+        ),
+        "invalid cache"
+    );
+
+    // Is there a non-negative integer n such that An+B=index?
+    match index.checked_sub(b) {
+        None => false,
+        Some(an) => match an.checked_div(a) {
+            Some(n) => n >= 0 && a * n == an,
+            None /* a == 0 */ => an == 0,
+        },
+    }
+    .into()
+}
+
+#[inline]
+fn nth_child_index<E>(
+    element: &E,
+    context: &mut MatchingContext<E::Impl>,
+    selectors: &[Selector<E::Impl>],
+    is_of_type: bool,
+    is_from_end: bool,
+    check_cache: bool,
+    rightmost: SubjectOrPseudoElement,
+) -> i32
+where
+    E: Element,
+{
+    // The traversal mostly processes siblings left to right. So when we walk
+    // siblings to the right when computing NthLast/NthLastOfType we're unlikely
+    // to get cache hits along the way. As such, we take the hit of walking the
+    // siblings to the left checking the cache in the is_from_end case (this
+    // matches what Gecko does). The indices-from-the-left is handled during the
+    // regular look further below.
+    if check_cache &&
+        is_from_end &&
+        !context
+            .nth_index_cache(is_of_type, is_from_end, selectors)
+            .is_empty()
+    {
+        let mut index: i32 = 1;
+        let mut curr = element.clone();
+        while let Some(e) = curr.prev_sibling_element() {
+            curr = e;
+            let matches = if is_of_type {
+                element.is_same_type(&curr)
+            } else if !selectors.is_empty() {
+                matches_complex_selector_list(selectors, &curr, context, rightmost).to_bool(true)
+            } else {
+                true
+            };
+            if !matches {
+                continue;
+            }
+            if let Some(i) = context
+                .nth_index_cache(is_of_type, is_from_end, selectors)
+                .lookup(curr.opaque())
+            {
+                return i - index;
+            }
+            index += 1;
+        }
+    }
+
+    let mut index: i32 = 1;
+    let mut curr = element.clone();
+    let next = |e: E| {
+        if is_from_end {
+            e.next_sibling_element()
+        } else {
+            e.prev_sibling_element()
+        }
+    };
+    while let Some(e) = next(curr) {
+        curr = e;
+        let matches = if is_of_type {
+            element.is_same_type(&curr)
+        } else if !selectors.is_empty() {
+            matches_complex_selector_list(selectors, &curr, context, rightmost).to_bool(true)
+        } else {
+            true
+        };
+        if !matches {
+            continue;
+        }
+        // If we're computing indices from the left, check each element in the
+        // cache. We handle the indices-from-the-right case at the top of this
+        // function.
+        if !is_from_end && check_cache {
+            if let Some(i) = context
+                .nth_index_cache(is_of_type, is_from_end, selectors)
+                .lookup(curr.opaque())
+            {
+                return i + index;
+            }
+        }
+        index += 1;
+    }
+
+    index
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/nth_index_cache.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/nth_index_cache.rs
new file mode 100644
index 000000000000..b4b41578d028
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/nth_index_cache.rs
@@ -0,0 +1,102 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::hash::Hash;
+
+use crate::{parser::Selector, tree::OpaqueElement, SelectorImpl};
+use fxhash::FxHashMap;
+
+/// A cache to speed up matching of nth-index-like selectors.
+///
+/// See [1] for some discussion around the design tradeoffs.
+///
+/// [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1401855#c3
+#[derive(Default)]
+pub struct NthIndexCache {
+    nth: NthIndexCacheInner,
+    nth_of_selectors: NthIndexOfSelectorsCaches,
+    nth_last: NthIndexCacheInner,
+    nth_last_of_selectors: NthIndexOfSelectorsCaches,
+    nth_of_type: NthIndexCacheInner,
+    nth_last_of_type: NthIndexCacheInner,
+}
+
+impl NthIndexCache {
+    /// Gets the appropriate cache for the given parameters.
+    pub fn get<Impl: SelectorImpl>(
+        &mut self,
+        is_of_type: bool,
+        is_from_end: bool,
+        selectors: &[Selector<Impl>],
+    ) -> &mut NthIndexCacheInner {
+        if is_of_type {
+            return if is_from_end {
+                &mut self.nth_last_of_type
+            } else {
+                &mut self.nth_of_type
+            };
+        }
+        if !selectors.is_empty() {
+            return if is_from_end {
+                self.nth_last_of_selectors.lookup(selectors)
+            } else {
+                self.nth_of_selectors.lookup(selectors)
+            };
+        }
+        if is_from_end {
+            &mut self.nth_last
+        } else {
+            &mut self.nth
+        }
+    }
+}
+
+#[derive(Hash, Eq, PartialEq)]
+struct SelectorListCacheKey(usize);
+
+/// Use the selector list's pointer as the cache key
+impl SelectorListCacheKey {
+    // :nth-child of selectors are reference-counted with `ThinArc`, so we know their pointers are stable.
+    fn new<Impl: SelectorImpl>(selectors: &[Selector<Impl>]) -> Self {
+        Self(selectors.as_ptr() as usize)
+    }
+}
+
+/// Use a different map of cached indices per :nth-child's or :nth-last-child's selector list
+#[derive(Default)]
+pub struct NthIndexOfSelectorsCaches(FxHashMap<SelectorListCacheKey, NthIndexCacheInner>);
+
+/// Get or insert a map of cached incides for the selector list of this
+/// particular :nth-child or :nth-last-child pseudoclass
+impl NthIndexOfSelectorsCaches {
+    pub fn lookup<Impl: SelectorImpl>(
+        &mut self,
+        selectors: &[Selector<Impl>],
+    ) -> &mut NthIndexCacheInner {
+        self.0
+            .entry(SelectorListCacheKey::new(selectors))
+            .or_default()
+    }
+}
+
+/// The concrete per-pseudo-class cache.
+#[derive(Default)]
+pub struct NthIndexCacheInner(FxHashMap<OpaqueElement, i32>);
+
+impl NthIndexCacheInner {
+    /// Does a lookup for a given element in the cache.
+    pub fn lookup(&mut self, el: OpaqueElement) -> Option<i32> {
+        self.0.get(&el).copied()
+    }
+
+    /// Inserts an entry into the cache.
+    pub fn insert(&mut self, element: OpaqueElement, index: i32) {
+        self.0.insert(element, index);
+    }
+
+    /// Returns whether the cache is empty.
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/parser.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/parser.rs
new file mode 100644
index 000000000000..b993785c2b1e
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/parser.rs
@@ -0,0 +1,4711 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::attr::{AttrSelectorOperator, AttrSelectorWithOptionalNamespace};
+use crate::attr::{NamespaceConstraint, ParsedAttrSelectorOperation, ParsedCaseSensitivity};
+use crate::bloom::BLOOM_HASH_MASK;
+use crate::builder::{
+    relative_selector_list_specificity_and_flags, selector_list_specificity_and_flags,
+    SelectorBuilder, SelectorFlags, Specificity, SpecificityAndFlags,
+};
+use crate::context::QuirksMode;
+use crate::sink::Push;
+use crate::visitor::SelectorListKind;
+pub use crate::visitor::SelectorVisitor;
+use cssparser::parse_nth;
+use cssparser::{BasicParseError, BasicParseErrorKind, ParseError, ParseErrorKind};
+use cssparser::{CowRcStr, Delimiter, SourceLocation};
+use cssparser::{Parser as CssParser, ToCss, Token};
+use precomputed_hash::PrecomputedHash;
+use servo_arc::{Arc, ArcUnionBorrow, ThinArc, ThinArcUnion, UniqueArc};
+use smallvec::SmallVec;
+use std::borrow::{Borrow, Cow};
+use std::fmt::{self, Debug};
+use std::iter::Rev;
+use std::slice;
+use bitflags::bitflags;
+use cssparser::match_ignore_ascii_case;
+use debug_unreachable::debug_unreachable;
+
+#[cfg(feature = "to_shmem")]
+use to_shmem_derive::ToShmem;
+
+/// A trait that represents a pseudo-element.
+pub trait PseudoElement: Sized + ToCss {
+    /// The `SelectorImpl` this pseudo-element is used for.
+    type Impl: SelectorImpl;
+
+    /// Whether the pseudo-element supports a given state selector to the right
+    /// of it.
+    fn accepts_state_pseudo_classes(&self) -> bool {
+        false
+    }
+
+    /// Whether this pseudo-element is valid after a ::slotted(..) pseudo.
+    fn valid_after_slotted(&self) -> bool {
+        false
+    }
+
+    /// The count we contribute to the specificity from this pseudo-element.
+    fn specificity_count(&self) -> u32 {
+        1
+    }
+
+    /// Whether this pseudo-element is in a pseudo-element tree (excluding the pseudo-element
+    /// root).
+    /// https://drafts.csswg.org/css-view-transitions-1/#pseudo-root
+    fn is_in_pseudo_element_tree(&self) -> bool {
+        false
+    }
+}
+
+/// A trait that represents a pseudo-class.
+pub trait NonTSPseudoClass: Sized + ToCss {
+    /// The `SelectorImpl` this pseudo-element is used for.
+    type Impl: SelectorImpl;
+
+    /// Whether this pseudo-class is :active or :hover.
+    fn is_active_or_hover(&self) -> bool;
+
+    /// Whether this pseudo-class belongs to:
+    ///
+    /// https://drafts.csswg.org/selectors-4/#useraction-pseudos
+    fn is_user_action_state(&self) -> bool;
+
+    fn visit<V>(&self, _visitor: &mut V) -> bool
+    where
+        V: SelectorVisitor<Impl = Self::Impl>,
+    {
+        true
+    }
+}
+
+/// Returns a Cow::Borrowed if `s` is already ASCII lowercase, and a
+/// Cow::Owned if `s` had to be converted into ASCII lowercase.
+fn to_ascii_lowercase(s: &str) -> Cow<str> {
+    if let Some(first_uppercase) = s.bytes().position(|byte| byte >= b'A' && byte <= b'Z') {
+        let mut string = s.to_owned();
+        string[first_uppercase..].make_ascii_lowercase();
+        string.into()
+    } else {
+        s.into()
+    }
+}
+
+bitflags! {
+    /// Flags that indicate at which point of parsing a selector are we.
+    #[derive(Copy, Clone)]
+    struct SelectorParsingState: u16 {
+        /// Whether we should avoid adding default namespaces to selectors that
+        /// aren't type or universal selectors.
+        const SKIP_DEFAULT_NAMESPACE = 1 << 0;
+
+        /// Whether we've parsed a ::slotted() pseudo-element already.
+        ///
+        /// If so, then we can only parse a subset of pseudo-elements, and
+        /// whatever comes after them if so.
+        const AFTER_SLOTTED = 1 << 1;
+        /// Whether we've parsed a ::part() pseudo-element already.
+        ///
+        /// If so, then we can only parse a subset of pseudo-elements, and
+        /// whatever comes after them if so.
+        const AFTER_PART = 1 << 2;
+        /// Whether we've parsed a pseudo-element (as in, an
+        /// `Impl::PseudoElement` thus not accounting for `::slotted` or
+        /// `::part`) already.
+        ///
+        /// If so, then other pseudo-elements and most other selectors are
+        /// disallowed.
+        const AFTER_PSEUDO_ELEMENT = 1 << 3;
+        /// Whether we've parsed a non-stateful pseudo-element (again, as-in
+        /// `Impl::PseudoElement`) already. If so, then other pseudo-classes are
+        /// disallowed. If this flag is set, `AFTER_PSEUDO_ELEMENT` must be set
+        /// as well.
+        const AFTER_NON_STATEFUL_PSEUDO_ELEMENT = 1 << 4;
+
+        /// Whether we are after any of the pseudo-like things.
+        const AFTER_PSEUDO = Self::AFTER_PART.bits() | Self::AFTER_SLOTTED.bits() | Self::AFTER_PSEUDO_ELEMENT.bits();
+
+        /// Whether we explicitly disallow combinators.
+        const DISALLOW_COMBINATORS = 1 << 5;
+
+        /// Whether we explicitly disallow pseudo-element-like things.
+        const DISALLOW_PSEUDOS = 1 << 6;
+
+        /// Whether we explicitly disallow relative selectors (i.e. `:has()`).
+        const DISALLOW_RELATIVE_SELECTOR = 1 << 7;
+
+        /// Whether we've parsed a pseudo-element which is in a pseudo-element tree (i.e. it is a
+        /// descendant pseudo of a pseudo-element root).
+        const IN_PSEUDO_ELEMENT_TREE = 1 << 8;
+    }
+}
+
+impl SelectorParsingState {
+    #[inline]
+    fn allows_pseudos(self) -> bool {
+        // NOTE(emilio): We allow pseudos after ::part and such.
+        !self.intersects(Self::AFTER_PSEUDO_ELEMENT | Self::DISALLOW_PSEUDOS)
+    }
+
+    #[inline]
+    fn allows_slotted(self) -> bool {
+        !self.intersects(Self::AFTER_PSEUDO | Self::DISALLOW_PSEUDOS)
+    }
+
+    #[inline]
+    fn allows_part(self) -> bool {
+        !self.intersects(Self::AFTER_PSEUDO | Self::DISALLOW_PSEUDOS)
+    }
+
+    #[inline]
+    fn allows_non_functional_pseudo_classes(self) -> bool {
+        !self.intersects(Self::AFTER_SLOTTED | Self::AFTER_NON_STATEFUL_PSEUDO_ELEMENT)
+    }
+
+    #[inline]
+    fn allows_tree_structural_pseudo_classes(self) -> bool {
+        !self.intersects(Self::AFTER_PSEUDO) || self.intersects(Self::IN_PSEUDO_ELEMENT_TREE)
+    }
+
+    #[inline]
+    fn allows_combinators(self) -> bool {
+        !self.intersects(Self::DISALLOW_COMBINATORS)
+    }
+
+    #[inline]
+    fn allows_only_child_pseudo_class_only(self) -> bool {
+        self.intersects(Self::IN_PSEUDO_ELEMENT_TREE)
+    }
+}
+
+pub type SelectorParseError<'i> = ParseError<'i, SelectorParseErrorKind<'i>>;
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum SelectorParseErrorKind<'i> {
+    NoQualifiedNameInAttributeSelector(Token<'i>),
+    EmptySelector,
+    DanglingCombinator,
+    NonCompoundSelector,
+    NonPseudoElementAfterSlotted,
+    InvalidPseudoElementAfterSlotted,
+    InvalidPseudoElementInsideWhere,
+    InvalidState,
+    UnexpectedTokenInAttributeSelector(Token<'i>),
+    PseudoElementExpectedColon(Token<'i>),
+    PseudoElementExpectedIdent(Token<'i>),
+    NoIdentForPseudo(Token<'i>),
+    UnsupportedPseudoClassOrElement(CowRcStr<'i>),
+    UnexpectedIdent(CowRcStr<'i>),
+    ExpectedNamespace(CowRcStr<'i>),
+    ExpectedBarInAttr(Token<'i>),
+    BadValueInAttr(Token<'i>),
+    InvalidQualNameInAttr(Token<'i>),
+    ExplicitNamespaceUnexpectedToken(Token<'i>),
+    ClassNeedsIdent(Token<'i>),
+}
+
+macro_rules! with_all_bounds {
+    (
+        [ $( $InSelector: tt )* ]
+        [ $( $CommonBounds: tt )* ]
+        [ $( $FromStr: tt )* ]
+    ) => {
+        /// This trait allows to define the parser implementation in regards
+        /// of pseudo-classes/elements
+        ///
+        /// NB: We need Clone so that we can derive(Clone) on struct with that
+        /// are parameterized on SelectorImpl. See
+        /// <https://github.com/rust-lang/rust/issues/26925>
+        pub trait SelectorImpl: Clone + Debug + Sized + 'static {
+            type ExtraMatchingData<'a>: Sized + Default;
+            type AttrValue: $($InSelector)*;
+            type Identifier: $($InSelector)* + PrecomputedHash;
+            type LocalName: $($InSelector)* + Borrow<Self::BorrowedLocalName> + PrecomputedHash;
+            type NamespaceUrl: $($CommonBounds)* + Default + Borrow<Self::BorrowedNamespaceUrl> + PrecomputedHash;
+            type NamespacePrefix: $($InSelector)* + Default;
+            type BorrowedNamespaceUrl: ?Sized + Eq;
+            type BorrowedLocalName: ?Sized + Eq;
+
+            /// non tree-structural pseudo-classes
+            /// (see: https://drafts.csswg.org/selectors/#structural-pseudos)
+            type NonTSPseudoClass: $($CommonBounds)* + NonTSPseudoClass<Impl = Self>;
+
+            /// pseudo-elements
+            type PseudoElement: $($CommonBounds)* + PseudoElement<Impl = Self>;
+
+            /// Whether attribute hashes should be collected for filtering
+            /// purposes.
+            fn should_collect_attr_hash(_name: &Self::LocalName) -> bool {
+                false
+            }
+        }
+    }
+}
+
+macro_rules! with_bounds {
+    ( [ $( $CommonBounds: tt )* ] [ $( $FromStr: tt )* ]) => {
+        with_all_bounds! {
+            [$($CommonBounds)* + $($FromStr)* + ToCss]
+            [$($CommonBounds)*]
+            [$($FromStr)*]
+        }
+    }
+}
+
+with_bounds! {
+    [Clone + Eq]
+    [for<'a> From<&'a str>]
+}
+
+pub trait Parser<'i> {
+    type Impl: SelectorImpl;
+    type Error: 'i + From<SelectorParseErrorKind<'i>>;
+
+    /// Whether to parse the `::slotted()` pseudo-element.
+    fn parse_slotted(&self) -> bool {
+        false
+    }
+
+    /// Whether to parse the `::part()` pseudo-element.
+    fn parse_part(&self) -> bool {
+        false
+    }
+
+    /// Whether to parse the selector list of nth-child() or nth-last-child().
+    fn parse_nth_child_of(&self) -> bool {
+        false
+    }
+
+    /// Whether to parse `:is` and `:where` pseudo-classes.
+    fn parse_is_and_where(&self) -> bool {
+        false
+    }
+
+    /// Whether to parse the :has pseudo-class.
+    fn parse_has(&self) -> bool {
+        false
+    }
+
+    /// Whether to parse the '&' delimiter as a parent selector.
+    fn parse_parent_selector(&self) -> bool {
+        false
+    }
+
+    /// Whether the given function name is an alias for the `:is()` function.
+    fn is_is_alias(&self, _name: &str) -> bool {
+        false
+    }
+
+    /// Whether to parse the `:host` pseudo-class.
+    fn parse_host(&self) -> bool {
+        false
+    }
+
+    /// Whether to allow forgiving selector-list parsing.
+    fn allow_forgiving_selectors(&self) -> bool {
+        true
+    }
+
+    /// This function can return an "Err" pseudo-element in order to support CSS2.1
+    /// pseudo-elements.
+    fn parse_non_ts_pseudo_class(
+        &self,
+        location: SourceLocation,
+        name: CowRcStr<'i>,
+    ) -> Result<<Self::Impl as SelectorImpl>::NonTSPseudoClass, ParseError<'i, Self::Error>> {
+        Err(
+            location.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                name,
+            )),
+        )
+    }
+
+    fn parse_non_ts_functional_pseudo_class<'t>(
+        &self,
+        name: CowRcStr<'i>,
+        parser: &mut CssParser<'i, 't>,
+        _after_part: bool,
+    ) -> Result<<Self::Impl as SelectorImpl>::NonTSPseudoClass, ParseError<'i, Self::Error>> {
+        Err(
+            parser.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                name,
+            )),
+        )
+    }
+
+    fn parse_pseudo_element(
+        &self,
+        location: SourceLocation,
+        name: CowRcStr<'i>,
+    ) -> Result<<Self::Impl as SelectorImpl>::PseudoElement, ParseError<'i, Self::Error>> {
+        Err(
+            location.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                name,
+            )),
+        )
+    }
+
+    fn parse_functional_pseudo_element<'t>(
+        &self,
+        name: CowRcStr<'i>,
+        arguments: &mut CssParser<'i, 't>,
+    ) -> Result<<Self::Impl as SelectorImpl>::PseudoElement, ParseError<'i, Self::Error>> {
+        Err(
+            arguments.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                name,
+            )),
+        )
+    }
+
+    fn default_namespace(&self) -> Option<<Self::Impl as SelectorImpl>::NamespaceUrl> {
+        None
+    }
+
+    fn namespace_for_prefix(
+        &self,
+        _prefix: &<Self::Impl as SelectorImpl>::NamespacePrefix,
+    ) -> Option<<Self::Impl as SelectorImpl>::NamespaceUrl> {
+        None
+    }
+}
+
+/// A selector list is a tagged pointer with either a single selector, or a ThinArc<()> of multiple
+/// selectors.
+#[derive(Clone, Eq, Debug, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct SelectorList<Impl: SelectorImpl>(
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    ThinArcUnion<SpecificityAndFlags, Component<Impl>, (), Selector<Impl>>,
+);
+
+impl<Impl: SelectorImpl> SelectorList<Impl> {
+    /// See Arc::mark_as_intentionally_leaked
+    pub fn mark_as_intentionally_leaked(&self) {
+        if let ArcUnionBorrow::Second(ref list) = self.0.borrow() {
+            list.with_arc(|list| list.mark_as_intentionally_leaked())
+        }
+        self.slice().iter().for_each(|s| s.mark_as_intentionally_leaked())
+    }
+
+    pub fn from_one(selector: Selector<Impl>) -> Self {
+        #[cfg(debug_assertions)]
+        let selector_repr = unsafe { *(&selector as *const _ as *const usize) };
+        let list = Self(ThinArcUnion::from_first(selector.into_data()));
+        #[cfg(debug_assertions)]
+        debug_assert_eq!(
+            selector_repr,
+            unsafe { *(&list as *const _ as *const usize) },
+            "We rely on the same bit representation for the single selector variant"
+        );
+        list
+    }
+
+    pub fn from_iter(mut iter: impl ExactSizeIterator<Item = Selector<Impl>>) -> Self {
+        if iter.len() == 1 {
+            Self::from_one(iter.next().unwrap())
+        } else {
+            Self(ThinArcUnion::from_second(ThinArc::from_header_and_iter(
+                (),
+                iter,
+            )))
+        }
+    }
+
+    #[inline]
+    pub fn slice(&self) -> &[Selector<Impl>] {
+        match self.0.borrow() {
+            ArcUnionBorrow::First(..) => {
+                // SAFETY: see from_one.
+                let selector: &Selector<Impl> = unsafe { std::mem::transmute(self) };
+                std::slice::from_ref(selector)
+            },
+            ArcUnionBorrow::Second(list) => list.get().slice(),
+        }
+    }
+
+    #[inline]
+    pub fn len(&self) -> usize {
+        match self.0.borrow() {
+            ArcUnionBorrow::First(..) => 1,
+            ArcUnionBorrow::Second(list) => list.len(),
+        }
+    }
+
+    /// Returns the address on the heap of the ThinArc for memory reporting.
+    pub fn thin_arc_heap_ptr(&self) -> *const ::std::os::raw::c_void {
+        match self.0.borrow() {
+            ArcUnionBorrow::First(s) => s.with_arc(|a| a.heap_ptr()),
+            ArcUnionBorrow::Second(s) => s.with_arc(|a| a.heap_ptr()),
+        }
+    }
+}
+
+/// Uniquely identify a selector based on its components, which is behind ThinArc and
+/// is therefore stable.
+#[derive(Clone, Copy, Hash, Eq, PartialEq)]
+pub struct SelectorKey(usize);
+
+impl SelectorKey {
+    /// Create a new key based on the given selector.
+    pub fn new<Impl: SelectorImpl>(selector: &Selector<Impl>) -> Self {
+        Self(selector.0.slice().as_ptr() as usize)
+    }
+}
+
+/// Whether or not we're using forgiving parsing mode
+#[derive(PartialEq)]
+enum ForgivingParsing {
+    /// Discard the entire selector list upon encountering any invalid selector.
+    /// This is the default behavior for almost all of CSS.
+    No,
+    /// Ignore invalid selectors, potentially creating an empty selector list.
+    ///
+    /// This is the error recovery mode of :is() and :where()
+    Yes,
+}
+
+/// Flag indicating if we're parsing relative selectors.
+#[derive(Copy, Clone, PartialEq)]
+pub enum ParseRelative {
+    /// Expect selectors to start with a combinator, assuming descendant combinator if not present.
+    ForHas,
+    /// Allow selectors to start with a combinator, prepending a parent selector if so. Do nothing
+    /// otherwise
+    ForNesting,
+    /// Allow selectors to start with a combinator, prepending a scope selector if so. Do nothing
+    /// otherwise
+    ForScope,
+    /// Treat as parse error if any selector begins with a combinator.
+    No,
+}
+
+impl<Impl: SelectorImpl> SelectorList<Impl> {
+    /// Returns a selector list with a single `:scope` selector (with specificity)
+    pub fn scope() -> Self {
+        Self::from_one(Selector::scope())
+    }
+    /// Returns a selector list with a single implicit `:scope` selector (no specificity)
+    pub fn implicit_scope() -> Self {
+        Self::from_one(Selector::implicit_scope())
+    }
+
+    /// Parse a comma-separated list of Selectors.
+    /// <https://drafts.csswg.org/selectors/#grouping>
+    ///
+    /// Return the Selectors or Err if there is an invalid selector.
+    pub fn parse<'i, 't, P>(
+        parser: &P,
+        input: &mut CssParser<'i, 't>,
+        parse_relative: ParseRelative,
+    ) -> Result<Self, ParseError<'i, P::Error>>
+    where
+        P: Parser<'i, Impl = Impl>,
+    {
+        Self::parse_with_state(
+            parser,
+            input,
+            SelectorParsingState::empty(),
+            ForgivingParsing::No,
+            parse_relative,
+        )
+    }
+
+    /// Same as `parse`, but disallow parsing of pseudo-elements.
+    pub fn parse_disallow_pseudo<'i, 't, P>(
+        parser: &P,
+        input: &mut CssParser<'i, 't>,
+        parse_relative: ParseRelative,
+    ) -> Result<Self, ParseError<'i, P::Error>>
+    where
+        P: Parser<'i, Impl = Impl>,
+    {
+        Self::parse_with_state(
+            parser,
+            input,
+            SelectorParsingState::DISALLOW_PSEUDOS,
+            ForgivingParsing::No,
+            parse_relative,
+        )
+    }
+
+    pub fn parse_forgiving<'i, 't, P>(
+        parser: &P,
+        input: &mut CssParser<'i, 't>,
+        parse_relative: ParseRelative,
+    ) -> Result<Self, ParseError<'i, P::Error>>
+    where
+        P: Parser<'i, Impl = Impl>,
+    {
+        Self::parse_with_state(
+            parser,
+            input,
+            SelectorParsingState::empty(),
+            ForgivingParsing::Yes,
+            parse_relative,
+        )
+    }
+
+    #[inline]
+    fn parse_with_state<'i, 't, P>(
+        parser: &P,
+        input: &mut CssParser<'i, 't>,
+        state: SelectorParsingState,
+        recovery: ForgivingParsing,
+        parse_relative: ParseRelative,
+    ) -> Result<Self, ParseError<'i, P::Error>>
+    where
+        P: Parser<'i, Impl = Impl>,
+    {
+        let mut values = SmallVec::<[_; 4]>::new();
+        let forgiving = recovery == ForgivingParsing::Yes && parser.allow_forgiving_selectors();
+        loop {
+            let selector = input.parse_until_before(Delimiter::Comma, |input| {
+                let start = input.position();
+                let mut selector = parse_selector(parser, input, state, parse_relative);
+                if forgiving && (selector.is_err() || input.expect_exhausted().is_err()) {
+                    input.expect_no_error_token()?;
+                    selector = Ok(Selector::new_invalid(input.slice_from(start)));
+                }
+                selector
+            })?;
+
+            values.push(selector);
+
+            match input.next() {
+                Ok(&Token::Comma) => {},
+                Ok(_) => unreachable!(),
+                Err(_) => break,
+            }
+        }
+        Ok(Self::from_iter(values.into_iter()))
+    }
+
+    /// Replaces the parent selector in all the items of the selector list.
+    pub fn replace_parent_selector(&self, parent: &SelectorList<Impl>) -> Self {
+        Self::from_iter(
+            self.slice()
+                .iter()
+                .map(|selector| selector.replace_parent_selector(parent)),
+        )
+    }
+
+    /// Creates a SelectorList from a Vec of selectors. Used in tests.
+    #[allow(dead_code)]
+    pub(crate) fn from_vec(v: Vec<Selector<Impl>>) -> Self {
+        SelectorList::from_iter(v.into_iter())
+    }
+}
+
+/// Parses one compound selector suitable for nested stuff like :-moz-any, etc.
+fn parse_inner_compound_selector<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+) -> Result<Selector<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    parse_selector(
+        parser,
+        input,
+        state | SelectorParsingState::DISALLOW_PSEUDOS | SelectorParsingState::DISALLOW_COMBINATORS,
+        ParseRelative::No,
+    )
+}
+
+/// Ancestor hashes for the bloom filter. We precompute these and store them
+/// inline with selectors to optimize cache performance during matching.
+/// This matters a lot.
+///
+/// We use 4 hashes, which is copied from Gecko, who copied it from WebKit.
+/// Note that increasing the number of hashes here will adversely affect the
+/// cache hit when fast-rejecting long lists of Rules with inline hashes.
+///
+/// Because the bloom filter only uses the bottom 24 bits of the hash, we pack
+/// the fourth hash into the upper bits of the first three hashes in order to
+/// shrink Rule (whose size matters a lot). This scheme minimizes the runtime
+/// overhead of the packing for the first three hashes (we just need to mask
+/// off the upper bits) at the expense of making the fourth somewhat more
+/// complicated to assemble, because we often bail out before checking all the
+/// hashes.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct AncestorHashes {
+    pub packed_hashes: [u32; 3],
+}
+
+pub(crate) fn collect_selector_hashes<'a, Impl: SelectorImpl, Iter>(
+    iter: Iter,
+    quirks_mode: QuirksMode,
+    hashes: &mut [u32; 4],
+    len: &mut usize,
+    create_inner_iterator: fn(&'a Selector<Impl>) -> Iter,
+) -> bool
+where
+    Iter: Iterator<Item = &'a Component<Impl>>,
+{
+    for component in iter {
+        let hash = match *component {
+            Component::LocalName(LocalName {
+                ref name,
+                ref lower_name,
+            }) => {
+                // Only insert the local-name into the filter if it's all
+                // lowercase.  Otherwise we would need to test both hashes, and
+                // our data structures aren't really set up for that.
+                if name != lower_name {
+                    continue;
+                }
+                name.precomputed_hash()
+            },
+            Component::DefaultNamespace(ref url) | Component::Namespace(_, ref url) => {
+                url.precomputed_hash()
+            },
+            // In quirks mode, class and id selectors should match
+            // case-insensitively, so just avoid inserting them into the filter.
+            Component::ID(ref id) if quirks_mode != QuirksMode::Quirks => id.precomputed_hash(),
+            Component::Class(ref class) if quirks_mode != QuirksMode::Quirks => {
+                class.precomputed_hash()
+            },
+            Component::AttributeInNoNamespace { ref local_name, .. }
+                if Impl::should_collect_attr_hash(local_name) =>
+            {
+                // AttributeInNoNamespace is only used when local_name ==
+                // local_name_lower.
+                local_name.precomputed_hash()
+            },
+            Component::AttributeInNoNamespaceExists {
+                ref local_name,
+                ref local_name_lower,
+                ..
+            } => {
+                // Only insert the local-name into the filter if it's all
+                // lowercase.  Otherwise we would need to test both hashes, and
+                // our data structures aren't really set up for that.
+                if local_name != local_name_lower || !Impl::should_collect_attr_hash(local_name) {
+                    continue;
+                }
+                local_name.precomputed_hash()
+            },
+            Component::AttributeOther(ref selector) => {
+                if selector.local_name != selector.local_name_lower ||
+                    !Impl::should_collect_attr_hash(&selector.local_name)
+                {
+                    continue;
+                }
+                selector.local_name.precomputed_hash()
+            },
+            Component::Is(ref list) | Component::Where(ref list) => {
+                // :where and :is OR their selectors, so we can't put any hash
+                // in the filter if there's more than one selector, as that'd
+                // exclude elements that may match one of the other selectors.
+                let slice = list.slice();
+                if slice.len() == 1 &&
+                    !collect_selector_hashes(
+                        create_inner_iterator(&slice[0]),
+                        quirks_mode,
+                        hashes,
+                        len,
+                        create_inner_iterator,
+                    )
+                {
+                    return false;
+                }
+                continue;
+            },
+            _ => continue,
+        };
+
+        hashes[*len] = hash & BLOOM_HASH_MASK;
+        *len += 1;
+        if *len == hashes.len() {
+            return false;
+        }
+    }
+    true
+}
+
+fn collect_ancestor_hashes<Impl: SelectorImpl>(
+    iter: SelectorIter<Impl>,
+    quirks_mode: QuirksMode,
+    hashes: &mut [u32; 4],
+    len: &mut usize,
+) {
+    collect_selector_hashes(AncestorIter::new(iter), quirks_mode, hashes, len, |s| {
+        AncestorIter(s.iter())
+    });
+}
+
+impl AncestorHashes {
+    pub fn new<Impl: SelectorImpl>(selector: &Selector<Impl>, quirks_mode: QuirksMode) -> Self {
+        // Compute ancestor hashes for the bloom filter.
+        let mut hashes = [0u32; 4];
+        let mut len = 0;
+        collect_ancestor_hashes(selector.iter(), quirks_mode, &mut hashes, &mut len);
+        debug_assert!(len <= 4);
+
+        // Now, pack the fourth hash (if it exists) into the upper byte of each of
+        // the other three hashes.
+        if len == 4 {
+            let fourth = hashes[3];
+            hashes[0] |= (fourth & 0x000000ff) << 24;
+            hashes[1] |= (fourth & 0x0000ff00) << 16;
+            hashes[2] |= (fourth & 0x00ff0000) << 8;
+        }
+
+        AncestorHashes {
+            packed_hashes: [hashes[0], hashes[1], hashes[2]],
+        }
+    }
+
+    /// Returns the fourth hash, reassembled from parts.
+    pub fn fourth_hash(&self) -> u32 {
+        ((self.packed_hashes[0] & 0xff000000) >> 24) |
+            ((self.packed_hashes[1] & 0xff000000) >> 16) |
+            ((self.packed_hashes[2] & 0xff000000) >> 8)
+    }
+}
+
+#[inline]
+pub fn namespace_empty_string<Impl: SelectorImpl>() -> Impl::NamespaceUrl {
+    // Rust type’s default, not default namespace
+    Impl::NamespaceUrl::default()
+}
+
+type SelectorData<Impl> = ThinArc<SpecificityAndFlags, Component<Impl>>;
+
+bitflags! {
+    /// What kind of selectors potentially matching featureless shawdow host are present.
+    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+    pub struct FeaturelessHostMatches: u8 {
+        /// This selector matches featureless shadow host via `:host`.
+        const FOR_HOST = 1 << 0;
+        /// This selector matches featureless shadow host via `:scope`.
+        /// Featureless match applies only if we're:
+        /// 1) In a scoping context, AND
+        /// 2) The scope is a shadow host.
+        const FOR_SCOPE = 1 << 1;
+    }
+}
+
+impl FeaturelessHostMatches {
+    fn insert_not_empty(&mut self, other: Self) -> bool {
+        if other.is_empty() {
+            return false;
+        }
+        self.insert(other);
+        true
+    }
+}
+
+/// A Selector stores a sequence of simple selectors and combinators. The
+/// iterator classes allow callers to iterate at either the raw sequence level or
+/// at the level of sequences of simple selectors separated by combinators. Most
+/// callers want the higher-level iterator.
+///
+/// We store compound selectors internally right-to-left (in matching order).
+/// Additionally, we invert the order of top-level compound selectors so that
+/// each one matches left-to-right. This is because matching namespace, local name,
+/// id, and class are all relatively cheap, whereas matching pseudo-classes might
+/// be expensive (depending on the pseudo-class). Since authors tend to put the
+/// pseudo-classes on the right, it's faster to start matching on the left.
+///
+/// This reordering doesn't change the semantics of selector matching, and we
+/// handle it in to_css to make it invisible to serialization.
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+#[repr(transparent)]
+pub struct Selector<Impl: SelectorImpl>(
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))] SelectorData<Impl>,
+);
+
+impl<Impl: SelectorImpl> Selector<Impl> {
+    /// See Arc::mark_as_intentionally_leaked
+    pub fn mark_as_intentionally_leaked(&self) {
+        self.0.mark_as_intentionally_leaked()
+    }
+
+    fn scope() -> Self {
+        Self(ThinArc::from_header_and_iter(
+            SpecificityAndFlags {
+                specificity: Specificity::single_class_like().into(),
+                flags: SelectorFlags::HAS_SCOPE,
+            },
+            std::iter::once(Component::Scope),
+        ))
+    }
+
+    /// An implicit scope selector, much like :where(:scope).
+    fn implicit_scope() -> Self {
+        Self(ThinArc::from_header_and_iter(
+            SpecificityAndFlags {
+                specificity: 0,
+                flags: SelectorFlags::HAS_SCOPE,
+            },
+            std::iter::once(Component::ImplicitScope),
+        ))
+    }
+
+    #[inline]
+    pub fn specificity(&self) -> u32 {
+        self.0.header.specificity
+    }
+
+    #[inline]
+    pub(crate) fn flags(&self) -> SelectorFlags {
+        self.0.header.flags
+    }
+
+    #[inline]
+    pub fn has_pseudo_element(&self) -> bool {
+        self.flags().intersects(SelectorFlags::HAS_PSEUDO)
+    }
+
+    #[inline]
+    pub fn has_parent_selector(&self) -> bool {
+        self.flags().intersects(SelectorFlags::HAS_PARENT)
+    }
+
+    #[inline]
+    pub fn has_scope_selector(&self) -> bool {
+        self.flags().intersects(SelectorFlags::HAS_SCOPE)
+    }
+
+    #[inline]
+    pub fn is_slotted(&self) -> bool {
+        self.flags().intersects(SelectorFlags::HAS_SLOTTED)
+    }
+
+    #[inline]
+    pub fn is_part(&self) -> bool {
+        self.flags().intersects(SelectorFlags::HAS_PART)
+    }
+
+    #[inline]
+    pub fn parts(&self) -> Option<&[Impl::Identifier]> {
+        if !self.is_part() {
+            return None;
+        }
+
+        let mut iter = self.iter();
+        if self.has_pseudo_element() {
+            // Skip the pseudo-element.
+            for _ in &mut iter {}
+
+            let combinator = iter.next_sequence()?;
+            debug_assert_eq!(combinator, Combinator::PseudoElement);
+        }
+
+        for component in iter {
+            if let Component::Part(ref part) = *component {
+                return Some(part);
+            }
+        }
+
+        debug_assert!(false, "is_part() lied somehow?");
+        None
+    }
+
+    #[inline]
+    pub fn pseudo_element(&self) -> Option<&Impl::PseudoElement> {
+        if !self.has_pseudo_element() {
+            return None;
+        }
+
+        for component in self.iter() {
+            if let Component::PseudoElement(ref pseudo) = *component {
+                return Some(pseudo);
+            }
+        }
+
+        debug_assert!(false, "has_pseudo_element lied!");
+        None
+    }
+
+    /// Whether this selector (pseudo-element part excluded) matches every element.
+    ///
+    /// Used for "pre-computed" pseudo-elements in components/style/stylist.rs
+    #[inline]
+    pub fn is_universal(&self) -> bool {
+        self.iter_raw_match_order().all(|c| {
+            matches!(
+                *c,
+                Component::ExplicitUniversalType |
+                    Component::ExplicitAnyNamespace |
+                    Component::Combinator(Combinator::PseudoElement) |
+                    Component::PseudoElement(..)
+            )
+        })
+    }
+
+    /// Returns an iterator over this selector in matching order (right-to-left).
+    /// When a combinator is reached, the iterator will return None, and
+    /// next_sequence() may be called to continue to the next sequence.
+    #[inline]
+    pub fn iter(&self) -> SelectorIter<Impl> {
+        SelectorIter {
+            iter: self.iter_raw_match_order(),
+            next_combinator: None,
+        }
+    }
+
+    /// Same as `iter()`, but skips `RelativeSelectorAnchor` and its associated combinator.
+    #[inline]
+    pub fn iter_skip_relative_selector_anchor(&self) -> SelectorIter<Impl> {
+        if cfg!(debug_assertions) {
+            let mut selector_iter = self.iter_raw_parse_order_from(0);
+            assert!(
+                matches!(
+                    selector_iter.next().unwrap(),
+                    Component::RelativeSelectorAnchor
+                ),
+                "Relative selector does not start with RelativeSelectorAnchor"
+            );
+            assert!(
+                selector_iter.next().unwrap().is_combinator(),
+                "Relative combinator does not exist"
+            );
+        }
+
+        SelectorIter {
+            iter: self.0.slice()[..self.len() - 2].iter(),
+            next_combinator: None,
+        }
+    }
+
+    /// Whether this selector matches a featureless shadow host, with no combinators to the left, and
+    /// optionally has a pseudo-element to the right.
+    #[inline]
+    pub fn matches_featureless_host_selector_or_pseudo_element(&self) -> FeaturelessHostMatches {
+        let flags = self.flags();
+
+        let mut result = FeaturelessHostMatches::empty();
+        if flags.intersects(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT) {
+            return result;
+        }
+        if flags.intersects(SelectorFlags::HAS_HOST) {
+            result.insert(FeaturelessHostMatches::FOR_HOST);
+        }
+        if flags.intersects(SelectorFlags::HAS_SCOPE) {
+            result.insert(FeaturelessHostMatches::FOR_SCOPE);
+        }
+        result
+    }
+
+    /// Returns an iterator over this selector in matching order (right-to-left),
+    /// skipping the rightmost |offset| Components.
+    #[inline]
+    pub fn iter_from(&self, offset: usize) -> SelectorIter<Impl> {
+        let iter = self.0.slice()[offset..].iter();
+        SelectorIter {
+            iter,
+            next_combinator: None,
+        }
+    }
+
+    /// Returns the combinator at index `index` (zero-indexed from the right),
+    /// or panics if the component is not a combinator.
+    #[inline]
+    pub fn combinator_at_match_order(&self, index: usize) -> Combinator {
+        match self.0.slice()[index] {
+            Component::Combinator(c) => c,
+            ref other => panic!(
+                "Not a combinator: {:?}, {:?}, index: {}",
+                other, self, index
+            ),
+        }
+    }
+
+    /// Returns an iterator over the entire sequence of simple selectors and
+    /// combinators, in matching order (from right to left).
+    #[inline]
+    pub fn iter_raw_match_order(&self) -> slice::Iter<Component<Impl>> {
+        self.0.slice().iter()
+    }
+
+    /// Returns the combinator at index `index` (zero-indexed from the left),
+    /// or panics if the component is not a combinator.
+    #[inline]
+    pub fn combinator_at_parse_order(&self, index: usize) -> Combinator {
+        match self.0.slice()[self.len() - index - 1] {
+            Component::Combinator(c) => c,
+            ref other => panic!(
+                "Not a combinator: {:?}, {:?}, index: {}",
+                other, self, index
+            ),
+        }
+    }
+
+    /// Returns an iterator over the sequence of simple selectors and
+    /// combinators, in parse order (from left to right), starting from
+    /// `offset`.
+    #[inline]
+    pub fn iter_raw_parse_order_from(&self, offset: usize) -> Rev<slice::Iter<Component<Impl>>> {
+        self.0.slice()[..self.len() - offset].iter().rev()
+    }
+
+    /// Creates a Selector from a vec of Components, specified in parse order. Used in tests.
+    #[allow(dead_code)]
+    pub(crate) fn from_vec(
+        vec: Vec<Component<Impl>>,
+        specificity: u32,
+        flags: SelectorFlags,
+    ) -> Self {
+        let mut builder = SelectorBuilder::default();
+        for component in vec.into_iter() {
+            if let Some(combinator) = component.as_combinator() {
+                builder.push_combinator(combinator);
+            } else {
+                builder.push_simple_selector(component);
+            }
+        }
+        let spec = SpecificityAndFlags { specificity, flags };
+        Selector(builder.build_with_specificity_and_flags(spec, ParseRelative::No))
+    }
+
+    #[inline]
+    fn into_data(self) -> SelectorData<Impl> {
+        self.0
+    }
+
+    pub fn replace_parent_selector(&self, parent: &SelectorList<Impl>) -> Self {
+        let parent_specificity_and_flags =
+            selector_list_specificity_and_flags(parent.slice().iter());
+
+        let mut specificity = Specificity::from(self.specificity());
+        let mut flags = self.flags() - SelectorFlags::HAS_PARENT;
+
+        fn replace_parent_on_selector_list<Impl: SelectorImpl>(
+            orig: &[Selector<Impl>],
+            parent: &SelectorList<Impl>,
+            specificity: &mut Specificity,
+            flags: &mut SelectorFlags,
+            propagate_specificity: bool,
+            flags_to_propagate: SelectorFlags,
+        ) -> Option<SelectorList<Impl>> {
+            if !orig.iter().any(|s| s.has_parent_selector()) {
+                return None;
+            }
+
+            let result = SelectorList::from_iter(orig.iter().map(|s| {
+                s.replace_parent_selector(parent)
+            }));
+
+            let result_specificity_and_flags =
+                selector_list_specificity_and_flags(result.slice().iter());
+            if propagate_specificity {
+                *specificity += Specificity::from(
+                    result_specificity_and_flags.specificity -
+                        selector_list_specificity_and_flags(orig.iter()).specificity,
+                );
+            }
+            flags.insert(
+                result_specificity_and_flags
+                    .flags
+                    .intersection(flags_to_propagate),
+            );
+            Some(result)
+        }
+
+        fn replace_parent_on_relative_selector_list<Impl: SelectorImpl>(
+            orig: &[RelativeSelector<Impl>],
+            parent: &SelectorList<Impl>,
+            specificity: &mut Specificity,
+            flags: &mut SelectorFlags,
+            flags_to_propagate: SelectorFlags,
+        ) -> Vec<RelativeSelector<Impl>> {
+            let mut any = false;
+
+            let result = orig
+                .iter()
+                .map(|s| {
+                    if !s.selector.has_parent_selector() {
+                        return s.clone();
+                    }
+                    any = true;
+                    RelativeSelector {
+                        match_hint: s.match_hint,
+                        selector: s.selector.replace_parent_selector(parent),
+                    }
+                })
+                .collect();
+
+            if !any {
+                return result;
+            }
+
+            let result_specificity_and_flags =
+                relative_selector_list_specificity_and_flags(&result);
+            flags.insert(
+                result_specificity_and_flags
+                    .flags
+                    .intersection(flags_to_propagate),
+            );
+            *specificity += Specificity::from(
+                result_specificity_and_flags.specificity -
+                    relative_selector_list_specificity_and_flags(orig).specificity,
+            );
+            result
+        }
+
+        fn replace_parent_on_selector<Impl: SelectorImpl>(
+            orig: &Selector<Impl>,
+            parent: &SelectorList<Impl>,
+            specificity: &mut Specificity,
+            flags: &mut SelectorFlags,
+            flags_to_propagate: SelectorFlags,
+        ) -> Selector<Impl> {
+            let new_selector = orig.replace_parent_selector(parent);
+            *specificity += Specificity::from(new_selector.specificity() - orig.specificity());
+            flags.insert(new_selector.flags().intersection(flags_to_propagate));
+            new_selector
+        }
+
+        if !self.has_parent_selector() {
+            return self.clone();
+        }
+
+        let iter = self.iter_raw_match_order().map(|component| {
+            use self::Component::*;
+            match *component {
+                LocalName(..) |
+                ID(..) |
+                Class(..) |
+                AttributeInNoNamespaceExists { .. } |
+                AttributeInNoNamespace { .. } |
+                AttributeOther(..) |
+                ExplicitUniversalType |
+                ExplicitAnyNamespace |
+                ExplicitNoNamespace |
+                DefaultNamespace(..) |
+                Namespace(..) |
+                Root |
+                Empty |
+                Scope |
+                ImplicitScope |
+                Nth(..) |
+                NonTSPseudoClass(..) |
+                PseudoElement(..) |
+                Combinator(..) |
+                Host(None) |
+                Part(..) |
+                Invalid(..) |
+                RelativeSelectorAnchor => component.clone(),
+                ParentSelector => {
+                    specificity += Specificity::from(parent_specificity_and_flags.specificity);
+                    flags.insert(
+                        parent_specificity_and_flags
+                            .flags
+                            .intersection(SelectorFlags::for_nesting()),
+                    );
+                    Is(parent.clone())
+                },
+                Negation(ref selectors) => {
+                    Negation(
+                        replace_parent_on_selector_list(
+                            selectors.slice(),
+                            parent,
+                            &mut specificity,
+                            &mut flags,
+                            /* propagate_specificity = */ true,
+                            SelectorFlags::for_nesting(),
+                        )
+                        .unwrap_or_else(|| selectors.clone()),
+                    )
+                },
+                Is(ref selectors) => {
+                    Is(replace_parent_on_selector_list(
+                        selectors.slice(),
+                        parent,
+                        &mut specificity,
+                        &mut flags,
+                        /* propagate_specificity = */ true,
+                        SelectorFlags::for_nesting(),
+                    )
+                    .unwrap_or_else(|| selectors.clone()))
+                },
+                Where(ref selectors) => {
+                    Where(
+                        replace_parent_on_selector_list(
+                            selectors.slice(),
+                            parent,
+                            &mut specificity,
+                            &mut flags,
+                            /* propagate_specificity = */ false,
+                            SelectorFlags::for_nesting(),
+                        )
+                        .unwrap_or_else(|| selectors.clone()),
+                    )
+                },
+                Has(ref selectors) => Has(replace_parent_on_relative_selector_list(
+                    selectors,
+                    parent,
+                    &mut specificity,
+                    &mut flags,
+                    SelectorFlags::for_nesting(),
+                )
+                .into_boxed_slice()),
+
+                Host(Some(ref selector)) => Host(Some(replace_parent_on_selector(
+                    selector,
+                    parent,
+                    &mut specificity,
+                    &mut flags,
+                    SelectorFlags::for_nesting() - SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                ))),
+                NthOf(ref data) => {
+                    let selectors = replace_parent_on_selector_list(
+                        data.selectors(),
+                        parent,
+                        &mut specificity,
+                        &mut flags,
+                        /* propagate_specificity = */ true,
+                        SelectorFlags::for_nesting(),
+                    );
+                    NthOf(match selectors {
+                        Some(s) => {
+                            NthOfSelectorData::new(data.nth_data(), s.slice().iter().cloned())
+                        },
+                        None => data.clone(),
+                    })
+                },
+                Slotted(ref selector) => Slotted(replace_parent_on_selector(
+                    selector,
+                    parent,
+                    &mut specificity,
+                    &mut flags,
+                    SelectorFlags::for_nesting(),
+                )),
+            }
+        });
+        let mut items = UniqueArc::from_header_and_iter(Default::default(), iter);
+        *items.header_mut() = SpecificityAndFlags {
+            specificity: specificity.into(),
+            flags,
+        };
+        Selector(items.shareable())
+    }
+
+    /// Returns count of simple selectors and combinators in the Selector.
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    /// Returns the address on the heap of the ThinArc for memory reporting.
+    pub fn thin_arc_heap_ptr(&self) -> *const ::std::os::raw::c_void {
+        self.0.heap_ptr()
+    }
+
+    /// Traverse selector components inside `self`.
+    ///
+    /// Implementations of this method should call `SelectorVisitor` methods
+    /// or other impls of `Visit` as appropriate based on the fields of `Self`.
+    ///
+    /// A return value of `false` indicates terminating the traversal.
+    /// It should be propagated with an early return.
+    /// On the contrary, `true` indicates that all fields of `self` have been traversed:
+    ///
+    /// ```rust,ignore
+    /// if !visitor.visit_simple_selector(&self.some_simple_selector) {
+    ///     return false;
+    /// }
+    /// if !self.some_component.visit(visitor) {
+    ///     return false;
+    /// }
+    /// true
+    /// ```
+    pub fn visit<V>(&self, visitor: &mut V) -> bool
+    where
+        V: SelectorVisitor<Impl = Impl>,
+    {
+        let mut current = self.iter();
+        let mut combinator = None;
+        loop {
+            if !visitor.visit_complex_selector(combinator) {
+                return false;
+            }
+
+            for selector in &mut current {
+                if !selector.visit(visitor) {
+                    return false;
+                }
+            }
+
+            combinator = current.next_sequence();
+            if combinator.is_none() {
+                break;
+            }
+        }
+
+        true
+    }
+
+    /// Parse a selector, without any pseudo-element.
+    #[inline]
+    pub fn parse<'i, 't, P>(
+        parser: &P,
+        input: &mut CssParser<'i, 't>,
+    ) -> Result<Self, ParseError<'i, P::Error>>
+    where
+        P: Parser<'i, Impl = Impl>,
+    {
+        parse_selector(
+            parser,
+            input,
+            SelectorParsingState::empty(),
+            ParseRelative::No,
+        )
+    }
+
+    pub fn new_invalid(s: &str) -> Self {
+        fn check_for_parent(input: &mut CssParser, has_parent: &mut bool) {
+            while let Ok(t) = input.next() {
+                match *t {
+                    Token::Function(_) |
+                    Token::ParenthesisBlock |
+                    Token::CurlyBracketBlock |
+                    Token::SquareBracketBlock => {
+                        let _ = input.parse_nested_block(
+                            |i| -> Result<(), ParseError<'_, BasicParseError>> {
+                                check_for_parent(i, has_parent);
+                                Ok(())
+                            },
+                        );
+                    },
+                    Token::Delim('&') => {
+                        *has_parent = true;
+                    },
+                    _ => {},
+                }
+                if *has_parent {
+                    break;
+                }
+            }
+        }
+        let mut has_parent = false;
+        {
+            let mut parser = cssparser::ParserInput::new(s);
+            let mut parser = CssParser::new(&mut parser);
+            check_for_parent(&mut parser, &mut has_parent);
+        }
+        Self(ThinArc::from_header_and_iter(
+            SpecificityAndFlags {
+                specificity: 0,
+                flags: if has_parent {
+                    SelectorFlags::HAS_PARENT
+                } else {
+                    SelectorFlags::empty()
+                },
+            },
+            std::iter::once(Component::Invalid(Arc::new(String::from(s.trim())))),
+        ))
+    }
+
+    /// Is the compound starting at the offset the subject compound, or referring to its pseudo-element?
+    pub fn is_rightmost(&self, offset: usize) -> bool {
+        // There can really be only one pseudo-element, and it's not really valid for anything else to
+        // follow it.
+        offset == 0 || matches!(self.combinator_at_match_order(offset - 1), Combinator::PseudoElement)
+    }
+}
+
+#[derive(Clone)]
+pub struct SelectorIter<'a, Impl: 'a + SelectorImpl> {
+    iter: slice::Iter<'a, Component<Impl>>,
+    next_combinator: Option<Combinator>,
+}
+
+impl<'a, Impl: 'a + SelectorImpl> SelectorIter<'a, Impl> {
+    /// Prepares this iterator to point to the next sequence to the left,
+    /// returning the combinator if the sequence was found.
+    #[inline]
+    pub fn next_sequence(&mut self) -> Option<Combinator> {
+        self.next_combinator.take()
+    }
+
+    /// Whether this selector is a featureless selector matching the shadow host, with no
+    /// combinators to the left.
+    #[inline]
+    pub(crate) fn is_featureless_host_selector(&mut self) -> FeaturelessHostMatches {
+        if self.selector_length() == 0 {
+            return FeaturelessHostMatches::empty();
+        }
+        let mut result = FeaturelessHostMatches::empty();
+        while let Some(c) = self.next() {
+            let component_matches = c.matches_featureless_host();
+            if component_matches.is_empty() {
+                return FeaturelessHostMatches::empty();
+            }
+            result.insert(component_matches);
+        }
+        if self.next_sequence().is_some() {
+            FeaturelessHostMatches::empty()
+        } else {
+            result
+        }
+    }
+
+    #[inline]
+    pub(crate) fn matches_for_stateless_pseudo_element(&mut self) -> bool {
+        let first = match self.next() {
+            Some(c) => c,
+            // Note that this is the common path that we keep inline: the
+            // pseudo-element not having anything to its right.
+            None => return true,
+        };
+        self.matches_for_stateless_pseudo_element_internal(first)
+    }
+
+    #[inline(never)]
+    fn matches_for_stateless_pseudo_element_internal(&mut self, first: &Component<Impl>) -> bool {
+        if !first.matches_for_stateless_pseudo_element() {
+            return false;
+        }
+        for component in self {
+            // The only other parser-allowed Components in this sequence are
+            // state pseudo-classes, or one of the other things that can contain
+            // them.
+            if !component.matches_for_stateless_pseudo_element() {
+                return false;
+            }
+        }
+        true
+    }
+
+    /// Returns remaining count of the simple selectors and combinators in the Selector.
+    #[inline]
+    pub fn selector_length(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<'a, Impl: SelectorImpl> Iterator for SelectorIter<'a, Impl> {
+    type Item = &'a Component<Impl>;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        debug_assert!(
+            self.next_combinator.is_none(),
+            "You should call next_sequence!"
+        );
+        match *self.iter.next()? {
+            Component::Combinator(c) => {
+                self.next_combinator = Some(c);
+                None
+            },
+            ref x => Some(x),
+        }
+    }
+}
+
+impl<'a, Impl: SelectorImpl> fmt::Debug for SelectorIter<'a, Impl> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let iter = self.iter.clone().rev();
+        for component in iter {
+            component.to_css(f)?
+        }
+        Ok(())
+    }
+}
+
+/// An iterator over all combinators in a selector. Does not traverse selectors within psuedoclasses.
+struct CombinatorIter<'a, Impl: 'a + SelectorImpl>(SelectorIter<'a, Impl>);
+impl<'a, Impl: 'a + SelectorImpl> CombinatorIter<'a, Impl> {
+    fn new(inner: SelectorIter<'a, Impl>) -> Self {
+        let mut result = CombinatorIter(inner);
+        result.consume_non_combinators();
+        result
+    }
+
+    fn consume_non_combinators(&mut self) {
+        while self.0.next().is_some() {}
+    }
+}
+
+impl<'a, Impl: SelectorImpl> Iterator for CombinatorIter<'a, Impl> {
+    type Item = Combinator;
+    fn next(&mut self) -> Option<Self::Item> {
+        let result = self.0.next_sequence();
+        self.consume_non_combinators();
+        result
+    }
+}
+
+/// An iterator over all simple selectors belonging to ancestors.
+struct AncestorIter<'a, Impl: 'a + SelectorImpl>(SelectorIter<'a, Impl>);
+impl<'a, Impl: 'a + SelectorImpl> AncestorIter<'a, Impl> {
+    /// Creates an AncestorIter. The passed-in iterator is assumed to point to
+    /// the beginning of the child sequence, which will be skipped.
+    fn new(inner: SelectorIter<'a, Impl>) -> Self {
+        let mut result = AncestorIter(inner);
+        result.skip_until_ancestor();
+        result
+    }
+
+    /// Skips a sequence of simple selectors and all subsequent sequences until
+    /// a non-pseudo-element ancestor combinator is reached.
+    fn skip_until_ancestor(&mut self) {
+        loop {
+            while self.0.next().is_some() {}
+            // If this is ever changed to stop at the "pseudo-element"
+            // combinator, we will need to fix the way we compute hashes for
+            // revalidation selectors.
+            if self.0.next_sequence().map_or(true, |x| {
+                matches!(x, Combinator::Child | Combinator::Descendant)
+            }) {
+                break;
+            }
+        }
+    }
+}
+
+impl<'a, Impl: SelectorImpl> Iterator for AncestorIter<'a, Impl> {
+    type Item = &'a Component<Impl>;
+    fn next(&mut self) -> Option<Self::Item> {
+        // Grab the next simple selector in the sequence if available.
+        let next = self.0.next();
+        if next.is_some() {
+            return next;
+        }
+
+        // See if there are more sequences. If so, skip any non-ancestor sequences.
+        if let Some(combinator) = self.0.next_sequence() {
+            if !matches!(combinator, Combinator::Child | Combinator::Descendant) {
+                self.skip_until_ancestor();
+            }
+        }
+
+        self.0.next()
+    }
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum Combinator {
+    Child,        //  >
+    Descendant,   // space
+    NextSibling,  // +
+    LaterSibling, // ~
+    /// A dummy combinator we use to the left of pseudo-elements.
+    ///
+    /// It serializes as the empty string, and acts effectively as a child
+    /// combinator in most cases.  If we ever actually start using a child
+    /// combinator for this, we will need to fix up the way hashes are computed
+    /// for revalidation selectors.
+    PseudoElement,
+    /// Another combinator used for ::slotted(), which represent the jump from
+    /// a node to its assigned slot.
+    SlotAssignment,
+    /// Another combinator used for `::part()`, which represents the jump from
+    /// the part to the containing shadow host.
+    Part,
+}
+
+impl Combinator {
+    /// Returns true if this combinator is a child or descendant combinator.
+    #[inline]
+    pub fn is_ancestor(&self) -> bool {
+        matches!(
+            *self,
+            Combinator::Child |
+                Combinator::Descendant |
+                Combinator::PseudoElement |
+                Combinator::SlotAssignment
+        )
+    }
+
+    /// Returns true if this combinator is a pseudo-element combinator.
+    #[inline]
+    pub fn is_pseudo_element(&self) -> bool {
+        matches!(*self, Combinator::PseudoElement)
+    }
+
+    /// Returns true if this combinator is a next- or later-sibling combinator.
+    #[inline]
+    pub fn is_sibling(&self) -> bool {
+        matches!(*self, Combinator::NextSibling | Combinator::LaterSibling)
+    }
+}
+
+/// An enum for the different types of :nth- pseudoclasses
+#[derive(Copy, Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub enum NthType {
+    Child,
+    LastChild,
+    OnlyChild,
+    OfType,
+    LastOfType,
+    OnlyOfType,
+}
+
+impl NthType {
+    pub fn is_only(self) -> bool {
+        self == Self::OnlyChild || self == Self::OnlyOfType
+    }
+
+    pub fn is_of_type(self) -> bool {
+        self == Self::OfType || self == Self::LastOfType || self == Self::OnlyOfType
+    }
+
+    pub fn is_from_end(self) -> bool {
+        self == Self::LastChild || self == Self::LastOfType
+    }
+}
+
+/// The properties that comprise an :nth- pseudoclass as of Selectors 3 (e.g.,
+/// nth-child(An+B)).
+/// https://www.w3.org/TR/selectors-3/#nth-child-pseudo
+#[derive(Copy, Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct NthSelectorData {
+    pub ty: NthType,
+    pub is_function: bool,
+    pub a: i32,
+    pub b: i32,
+}
+
+impl NthSelectorData {
+    /// Returns selector data for :only-{child,of-type}
+    #[inline]
+    pub const fn only(of_type: bool) -> Self {
+        Self {
+            ty: if of_type {
+                NthType::OnlyOfType
+            } else {
+                NthType::OnlyChild
+            },
+            is_function: false,
+            a: 0,
+            b: 1,
+        }
+    }
+
+    /// Returns selector data for :first-{child,of-type}
+    #[inline]
+    pub const fn first(of_type: bool) -> Self {
+        Self {
+            ty: if of_type {
+                NthType::OfType
+            } else {
+                NthType::Child
+            },
+            is_function: false,
+            a: 0,
+            b: 1,
+        }
+    }
+
+    /// Returns selector data for :last-{child,of-type}
+    #[inline]
+    pub const fn last(of_type: bool) -> Self {
+        Self {
+            ty: if of_type {
+                NthType::LastOfType
+            } else {
+                NthType::LastChild
+            },
+            is_function: false,
+            a: 0,
+            b: 1,
+        }
+    }
+
+    /// Returns true if this is an edge selector that is not `:*-of-type``
+    #[inline]
+    pub fn is_simple_edge(&self) -> bool {
+        self.a == 0 && self.b == 1 && !self.ty.is_of_type() && !self.ty.is_only()
+    }
+
+    /// Writes the beginning of the selector.
+    #[inline]
+    fn write_start<W: fmt::Write>(&self, dest: &mut W) -> fmt::Result {
+        dest.write_str(match self.ty {
+            NthType::Child if self.is_function => ":nth-child(",
+            NthType::Child => ":first-child",
+            NthType::LastChild if self.is_function => ":nth-last-child(",
+            NthType::LastChild => ":last-child",
+            NthType::OfType if self.is_function => ":nth-of-type(",
+            NthType::OfType => ":first-of-type",
+            NthType::LastOfType if self.is_function => ":nth-last-of-type(",
+            NthType::LastOfType => ":last-of-type",
+            NthType::OnlyChild => ":only-child",
+            NthType::OnlyOfType => ":only-of-type",
+        })
+    }
+
+    /// Serialize <an+b> (part of the CSS Syntax spec, but currently only used here).
+    /// <https://drafts.csswg.org/css-syntax-3/#serialize-an-anb-value>
+    #[inline]
+    fn write_affine<W: fmt::Write>(&self, dest: &mut W) -> fmt::Result {
+        match (self.a, self.b) {
+            (0, 0) => dest.write_char('0'),
+
+            (1, 0) => dest.write_char('n'),
+            (-1, 0) => dest.write_str("-n"),
+            (_, 0) => write!(dest, "{}n", self.a),
+
+            (0, _) => write!(dest, "{}", self.b),
+            (1, _) => write!(dest, "n{:+}", self.b),
+            (-1, _) => write!(dest, "-n{:+}", self.b),
+            (_, _) => write!(dest, "{}n{:+}", self.a, self.b),
+        }
+    }
+}
+
+/// The properties that comprise an :nth- pseudoclass as of Selectors 4 (e.g.,
+/// nth-child(An+B [of S]?)).
+/// https://www.w3.org/TR/selectors-4/#nth-child-pseudo
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct NthOfSelectorData<Impl: SelectorImpl>(
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))] ThinArc<NthSelectorData, Selector<Impl>>,
+);
+
+impl<Impl: SelectorImpl> NthOfSelectorData<Impl> {
+    /// Returns selector data for :nth-{,last-}{child,of-type}(An+B [of S])
+    #[inline]
+    pub fn new<I>(nth_data: &NthSelectorData, selectors: I) -> Self
+    where
+        I: Iterator<Item = Selector<Impl>> + ExactSizeIterator,
+    {
+        Self(ThinArc::from_header_and_iter(*nth_data, selectors))
+    }
+
+    /// Returns the An+B part of the selector
+    #[inline]
+    pub fn nth_data(&self) -> &NthSelectorData {
+        &self.0.header
+    }
+
+    /// Returns the selector list part of the selector
+    #[inline]
+    pub fn selectors(&self) -> &[Selector<Impl>] {
+        self.0.slice()
+    }
+}
+
+/// Flag indicating where a given relative selector's match would be contained.
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+pub enum RelativeSelectorMatchHint {
+    /// Within this element's subtree.
+    InSubtree,
+    /// Within this element's direct children.
+    InChild,
+    /// This element's next sibling.
+    InNextSibling,
+    /// Within this element's next sibling's subtree.
+    InNextSiblingSubtree,
+    /// Within this element's subsequent siblings.
+    InSibling,
+    /// Across this element's subsequent siblings and their subtrees.
+    InSiblingSubtree,
+}
+
+impl RelativeSelectorMatchHint {
+    /// Create a new relative selector match hint based on its composition.
+    pub fn new(
+        relative_combinator: Combinator,
+        has_child_or_descendants: bool,
+        has_adjacent_or_next_siblings: bool,
+    ) -> Self {
+        match relative_combinator {
+            Combinator::Descendant => RelativeSelectorMatchHint::InSubtree,
+            Combinator::Child => {
+                if !has_child_or_descendants {
+                    RelativeSelectorMatchHint::InChild
+                } else {
+                    // Technically, for any composition that consists of child combinators only,
+                    // the search space is depth-constrained, but it's probably not worth optimizing for.
+                    RelativeSelectorMatchHint::InSubtree
+                }
+            },
+            Combinator::NextSibling => {
+                if !has_child_or_descendants && !has_adjacent_or_next_siblings {
+                    RelativeSelectorMatchHint::InNextSibling
+                } else if !has_child_or_descendants && has_adjacent_or_next_siblings {
+                    RelativeSelectorMatchHint::InSibling
+                } else if has_child_or_descendants && !has_adjacent_or_next_siblings {
+                    // Match won't cross multiple siblings.
+                    RelativeSelectorMatchHint::InNextSiblingSubtree
+                } else {
+                    RelativeSelectorMatchHint::InSiblingSubtree
+                }
+            },
+            Combinator::LaterSibling => {
+                if !has_child_or_descendants {
+                    RelativeSelectorMatchHint::InSibling
+                } else {
+                    // Even if the match may not cross multiple siblings, we have to look until
+                    // we find a match anyway.
+                    RelativeSelectorMatchHint::InSiblingSubtree
+                }
+            },
+            Combinator::Part | Combinator::PseudoElement | Combinator::SlotAssignment => {
+                debug_assert!(false, "Unexpected relative combinator");
+                RelativeSelectorMatchHint::InSubtree
+            },
+        }
+    }
+
+    /// Is the match traversal direction towards the descendant of this element (As opposed to siblings)?
+    pub fn is_descendant_direction(&self) -> bool {
+        matches!(*self, Self::InChild | Self::InSubtree)
+    }
+
+    /// Is the match traversal terminated at the next sibling?
+    pub fn is_next_sibling(&self) -> bool {
+        matches!(*self, Self::InNextSibling | Self::InNextSiblingSubtree)
+    }
+
+    /// Does the match involve matching the subtree?
+    pub fn is_subtree(&self) -> bool {
+        matches!(
+            *self,
+            Self::InSubtree | Self::InSiblingSubtree | Self::InNextSiblingSubtree
+        )
+    }
+}
+
+/// Count of combinators in a given relative selector, not traversing selectors of pseudoclasses.
+#[derive(Clone, Copy)]
+pub struct RelativeSelectorCombinatorCount {
+    relative_combinator: Combinator,
+    pub child_or_descendants: usize,
+    pub adjacent_or_next_siblings: usize,
+}
+
+impl RelativeSelectorCombinatorCount {
+    /// Create a new relative selector combinator count from a given relative selector.
+    pub fn new<Impl: SelectorImpl>(relative_selector: &RelativeSelector<Impl>) -> Self {
+        let mut result = RelativeSelectorCombinatorCount {
+            relative_combinator: relative_selector.selector.combinator_at_parse_order(1),
+            child_or_descendants: 0,
+            adjacent_or_next_siblings: 0,
+        };
+
+        for combinator in CombinatorIter::new(
+            relative_selector
+                .selector
+                .iter_skip_relative_selector_anchor(),
+        ) {
+            match combinator {
+                Combinator::Descendant | Combinator::Child => {
+                    result.child_or_descendants += 1;
+                },
+                Combinator::NextSibling | Combinator::LaterSibling => {
+                    result.adjacent_or_next_siblings += 1;
+                },
+                Combinator::Part | Combinator::PseudoElement | Combinator::SlotAssignment => {
+                    continue
+                },
+            };
+        }
+        result
+    }
+
+    /// Get the match hint based on the current combinator count.
+    pub fn get_match_hint(&self) -> RelativeSelectorMatchHint {
+        RelativeSelectorMatchHint::new(
+            self.relative_combinator,
+            self.child_or_descendants != 0,
+            self.adjacent_or_next_siblings != 0,
+        )
+    }
+}
+
+/// Storage for a relative selector.
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct RelativeSelector<Impl: SelectorImpl> {
+    /// Match space constraining hint.
+    pub match_hint: RelativeSelectorMatchHint,
+    /// The selector. Guaranteed to contain `RelativeSelectorAnchor` and the relative combinator in parse order.
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    pub selector: Selector<Impl>,
+}
+
+bitflags! {
+    /// Composition of combinators in a given selector, not traversing selectors of pseudoclasses.
+    #[derive(Clone, Debug, Eq, PartialEq)]
+    struct CombinatorComposition: u8 {
+        const DESCENDANTS = 1 << 0;
+        const SIBLINGS = 1 << 1;
+    }
+}
+
+impl CombinatorComposition {
+    fn for_relative_selector<Impl: SelectorImpl>(inner_selector: &Selector<Impl>) -> Self {
+        let mut result = CombinatorComposition::empty();
+        for combinator in CombinatorIter::new(inner_selector.iter_skip_relative_selector_anchor()) {
+            match combinator {
+                Combinator::Descendant | Combinator::Child => {
+                    result.insert(Self::DESCENDANTS);
+                },
+                Combinator::NextSibling | Combinator::LaterSibling => {
+                    result.insert(Self::SIBLINGS);
+                },
+                Combinator::Part | Combinator::PseudoElement | Combinator::SlotAssignment => {
+                    continue
+                },
+            };
+            if result.is_all() {
+                break;
+            }
+        }
+        return result;
+    }
+}
+
+impl<Impl: SelectorImpl> RelativeSelector<Impl> {
+    fn from_selector_list(selector_list: SelectorList<Impl>) -> Box<[Self]> {
+        let vec: Vec<Self> = selector_list
+            .slice()
+            .iter()
+            .map(|selector| {
+                // It's more efficient to keep track of all this during the parse time, but that seems like a lot of special
+                // case handling for what it's worth.
+                if cfg!(debug_assertions) {
+                    let relative_selector_anchor = selector.iter_raw_parse_order_from(0).next();
+                    debug_assert!(
+                        relative_selector_anchor.is_some(),
+                        "Relative selector is empty"
+                    );
+                    debug_assert!(
+                        matches!(
+                            relative_selector_anchor.unwrap(),
+                            Component::RelativeSelectorAnchor
+                        ),
+                        "Relative selector anchor is missing"
+                    );
+                }
+                // Leave a hint for narrowing down the search space when we're matching.
+                let composition = CombinatorComposition::for_relative_selector(&selector);
+                let match_hint = RelativeSelectorMatchHint::new(
+                    selector.combinator_at_parse_order(1),
+                    composition.intersects(CombinatorComposition::DESCENDANTS),
+                    composition.intersects(CombinatorComposition::SIBLINGS),
+                );
+                RelativeSelector {
+                    match_hint,
+                    selector: selector.clone(),
+                }
+            })
+            .collect();
+        vec.into_boxed_slice()
+    }
+}
+
+/// A CSS simple selector or combinator. We store both in the same enum for
+/// optimal packing and cache performance, see [1].
+///
+/// [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1357973
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub enum Component<Impl: SelectorImpl> {
+    LocalName(LocalName<Impl>),
+
+    ID(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::Identifier),
+    Class(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::Identifier),
+
+    AttributeInNoNamespaceExists {
+        #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+        local_name: Impl::LocalName,
+        local_name_lower: Impl::LocalName,
+    },
+    // Used only when local_name is already lowercase.
+    AttributeInNoNamespace {
+        local_name: Impl::LocalName,
+        operator: AttrSelectorOperator,
+        #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+        value: Impl::AttrValue,
+        case_sensitivity: ParsedCaseSensitivity,
+    },
+    // Use a Box in the less common cases with more data to keep size_of::<Component>() small.
+    AttributeOther(Box<AttrSelectorWithOptionalNamespace<Impl>>),
+
+    ExplicitUniversalType,
+    ExplicitAnyNamespace,
+
+    ExplicitNoNamespace,
+    DefaultNamespace(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::NamespaceUrl),
+    Namespace(
+        #[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::NamespacePrefix,
+        #[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::NamespaceUrl,
+    ),
+
+    /// Pseudo-classes
+    Negation(SelectorList<Impl>),
+    Root,
+    Empty,
+    Scope,
+    /// :scope added implicitly into scoped rules (i.e. In `@scope`) not
+    /// explicitly using `:scope` or `&` selectors.
+    ///
+    /// https://drafts.csswg.org/css-cascade-6/#scoped-rules
+    ///
+    /// Unlike the normal `:scope` selector, this does not add any specificity.
+    /// See https://github.com/w3c/csswg-drafts/issues/10196
+    ImplicitScope,
+    ParentSelector,
+    Nth(NthSelectorData),
+    NthOf(NthOfSelectorData<Impl>),
+    NonTSPseudoClass(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::NonTSPseudoClass),
+    /// The ::slotted() pseudo-element:
+    ///
+    /// https://drafts.csswg.org/css-scoping/#slotted-pseudo
+    ///
+    /// The selector here is a compound selector, that is, no combinators.
+    ///
+    /// NOTE(emilio): This should support a list of selectors, but as of this
+    /// writing no other browser does, and that allows them to put ::slotted()
+    /// in the rule hash, so we do that too.
+    ///
+    /// See https://github.com/w3c/csswg-drafts/issues/2158
+    Slotted(Selector<Impl>),
+    /// The `::part` pseudo-element.
+    ///   https://drafts.csswg.org/css-shadow-parts/#part
+    Part(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Box<[Impl::Identifier]>),
+    /// The `:host` pseudo-class:
+    ///
+    /// https://drafts.csswg.org/css-scoping/#host-selector
+    ///
+    /// NOTE(emilio): This should support a list of selectors, but as of this
+    /// writing no other browser does, and that allows them to put :host()
+    /// in the rule hash, so we do that too.
+    ///
+    /// See https://github.com/w3c/csswg-drafts/issues/2158
+    Host(Option<Selector<Impl>>),
+    /// The `:where` pseudo-class.
+    ///
+    /// https://drafts.csswg.org/selectors/#zero-matches
+    ///
+    /// The inner argument is conceptually a SelectorList, but we move the
+    /// selectors to the heap to keep Component small.
+    Where(SelectorList<Impl>),
+    /// The `:is` pseudo-class.
+    ///
+    /// https://drafts.csswg.org/selectors/#matches-pseudo
+    ///
+    /// Same comment as above re. the argument.
+    Is(SelectorList<Impl>),
+    /// The `:has` pseudo-class.
+    ///
+    /// https://drafts.csswg.org/selectors/#has-pseudo
+    ///
+    /// Same comment as above re. the argument.
+    Has(Box<[RelativeSelector<Impl>]>),
+    /// An invalid selector inside :is() / :where().
+    Invalid(Arc<String>),
+    /// An implementation-dependent pseudo-element selector.
+    PseudoElement(#[cfg_attr(feature = "to_shmem", shmem(field_bound))] Impl::PseudoElement),
+
+    Combinator(Combinator),
+
+    /// Used only for relative selectors, which starts with a combinator
+    /// (With an implied descendant combinator if not specified).
+    ///
+    /// https://drafts.csswg.org/selectors-4/#typedef-relative-selector
+    RelativeSelectorAnchor,
+}
+
+impl<Impl: SelectorImpl> Component<Impl> {
+    /// Returns true if this is a combinator.
+    #[inline]
+    pub fn is_combinator(&self) -> bool {
+        matches!(*self, Component::Combinator(_))
+    }
+
+    /// Returns true if this is a :host() selector.
+    #[inline]
+    pub fn is_host(&self) -> bool {
+        matches!(*self, Component::Host(..))
+    }
+
+    /// Returns if this component can match a featureless shadow host, and if so,
+    /// via which selector.
+    #[inline]
+    pub fn matches_featureless_host(&self) -> FeaturelessHostMatches {
+        match *self {
+            Component::Host(..) => FeaturelessHostMatches::FOR_HOST,
+            Component::Scope | Component::ImplicitScope => FeaturelessHostMatches::FOR_SCOPE,
+            Component::Where(ref l) | Component::Is(ref l) => {
+                debug_assert!(l.len() > 0, "Zero length selector?");
+                // TODO(emilio): For now we require that everything in logical combination can match
+                // the featureless shadow host, because not doing so brings up a fair amount of extra
+                // complexity (we can't make the decision on whether to walk out statically).
+                let mut result = FeaturelessHostMatches::empty();
+                for i in l.slice() {
+                    if !result.insert_not_empty(
+                        i.matches_featureless_host_selector_or_pseudo_element()
+                    ) {
+                        return FeaturelessHostMatches::empty();
+                    }
+                }
+                result
+            },
+            _ => FeaturelessHostMatches::empty(),
+        }
+    }
+
+    /// Returns the value as a combinator if applicable, None otherwise.
+    pub fn as_combinator(&self) -> Option<Combinator> {
+        match *self {
+            Component::Combinator(c) => Some(c),
+            _ => None,
+        }
+    }
+
+    /// Whether a given selector (to the right of a pseudo-element) should match for stateless
+    /// pseudo-elements. Note that generally nothing matches for those, but since we have :not(),
+    /// we still need to traverse nested selector lists.
+    fn matches_for_stateless_pseudo_element(&self) -> bool {
+        match *self {
+            Component::Negation(ref selectors) => !selectors.slice().iter().all(|selector| {
+                selector
+                    .iter_raw_match_order()
+                    .all(|c| c.matches_for_stateless_pseudo_element())
+            }),
+            Component::Is(ref selectors) | Component::Where(ref selectors) => {
+                selectors.slice().iter().any(|selector| {
+                    selector
+                        .iter_raw_match_order()
+                        .all(|c| c.matches_for_stateless_pseudo_element())
+                })
+            },
+            _ => false,
+        }
+    }
+
+    pub fn visit<V>(&self, visitor: &mut V) -> bool
+    where
+        V: SelectorVisitor<Impl = Impl>,
+    {
+        use self::Component::*;
+        if !visitor.visit_simple_selector(self) {
+            return false;
+        }
+
+        match *self {
+            Slotted(ref selector) => {
+                if !selector.visit(visitor) {
+                    return false;
+                }
+            },
+            Host(Some(ref selector)) => {
+                if !selector.visit(visitor) {
+                    return false;
+                }
+            },
+            AttributeInNoNamespaceExists {
+                ref local_name,
+                ref local_name_lower,
+            } => {
+                if !visitor.visit_attribute_selector(
+                    &NamespaceConstraint::Specific(&namespace_empty_string::<Impl>()),
+                    local_name,
+                    local_name_lower,
+                ) {
+                    return false;
+                }
+            },
+            AttributeInNoNamespace { ref local_name, .. } => {
+                if !visitor.visit_attribute_selector(
+                    &NamespaceConstraint::Specific(&namespace_empty_string::<Impl>()),
+                    local_name,
+                    local_name,
+                ) {
+                    return false;
+                }
+            },
+            AttributeOther(ref attr_selector) => {
+                let empty_string;
+                let namespace = match attr_selector.namespace() {
+                    Some(ns) => ns,
+                    None => {
+                        empty_string = crate::parser::namespace_empty_string::<Impl>();
+                        NamespaceConstraint::Specific(&empty_string)
+                    },
+                };
+                if !visitor.visit_attribute_selector(
+                    &namespace,
+                    &attr_selector.local_name,
+                    &attr_selector.local_name_lower,
+                ) {
+                    return false;
+                }
+            },
+
+            NonTSPseudoClass(ref pseudo_class) => {
+                if !pseudo_class.visit(visitor) {
+                    return false;
+                }
+            },
+            Negation(ref list) | Is(ref list) | Where(ref list) => {
+                let list_kind = SelectorListKind::from_component(self);
+                debug_assert!(!list_kind.is_empty());
+                if !visitor.visit_selector_list(list_kind, list.slice()) {
+                    return false;
+                }
+            },
+            NthOf(ref nth_of_data) => {
+                if !visitor.visit_selector_list(SelectorListKind::NTH_OF, nth_of_data.selectors()) {
+                    return false;
+                }
+            },
+            Has(ref list) => {
+                if !visitor.visit_relative_selector_list(list) {
+                    return false;
+                }
+            },
+            _ => {},
+        }
+
+        true
+    }
+
+    // Returns true if this has any selector that requires an index calculation. e.g.
+    // :nth-child, :first-child, etc. For nested selectors, return true only if the
+    // indexed selector is in its subject compound.
+    pub fn has_indexed_selector_in_subject(&self) -> bool {
+        match *self {
+            Component::NthOf(..) | Component::Nth(..) => return true,
+            Component::Is(ref selectors) |
+            Component::Where(ref selectors) |
+            Component::Negation(ref selectors) => {
+                // Check the subject compound.
+                for selector in selectors.slice() {
+                    let mut iter = selector.iter();
+                    while let Some(c) = iter.next() {
+                        if c.has_indexed_selector_in_subject() {
+                            return true;
+                        }
+                    }
+                }
+            },
+            _ => (),
+        };
+        false
+    }
+}
+
+#[derive(Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "to_shmem", derive(ToShmem))]
+#[cfg_attr(feature = "to_shmem", shmem(no_bounds))]
+pub struct LocalName<Impl: SelectorImpl> {
+    #[cfg_attr(feature = "to_shmem", shmem(field_bound))]
+    pub name: Impl::LocalName,
+    pub lower_name: Impl::LocalName,
+}
+
+impl<Impl: SelectorImpl> Debug for Selector<Impl> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str("Selector(")?;
+        self.to_css(f)?;
+        write!(
+            f,
+            ", specificity = {:#x}, flags = {:?})",
+            self.specificity(),
+            self.flags()
+        )
+    }
+}
+
+impl<Impl: SelectorImpl> Debug for Component<Impl> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.to_css(f)
+    }
+}
+impl<Impl: SelectorImpl> Debug for AttrSelectorWithOptionalNamespace<Impl> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.to_css(f)
+    }
+}
+impl<Impl: SelectorImpl> Debug for LocalName<Impl> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.to_css(f)
+    }
+}
+
+fn serialize_selector_list<'a, Impl, I, W>(iter: I, dest: &mut W) -> fmt::Result
+where
+    Impl: SelectorImpl,
+    I: Iterator<Item = &'a Selector<Impl>>,
+    W: fmt::Write,
+{
+    let mut first = true;
+    for selector in iter {
+        if !first {
+            dest.write_str(", ")?;
+        }
+        first = false;
+        selector.to_css(dest)?;
+    }
+    Ok(())
+}
+
+impl<Impl: SelectorImpl> ToCss for SelectorList<Impl> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        serialize_selector_list(self.slice().iter(), dest)
+    }
+}
+
+impl<Impl: SelectorImpl> ToCss for Selector<Impl> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        // Compound selectors invert the order of their contents, so we need to
+        // undo that during serialization.
+        //
+        // This two-iterator strategy involves walking over the selector twice.
+        // We could do something more clever, but selector serialization probably
+        // isn't hot enough to justify it, and the stringification likely
+        // dominates anyway.
+        //
+        // NB: A parse-order iterator is a Rev<>, which doesn't expose as_slice(),
+        // which we need for |split|. So we split by combinators on a match-order
+        // sequence and then reverse.
+
+        let mut combinators = self
+            .iter_raw_match_order()
+            .rev()
+            .filter_map(|x| x.as_combinator());
+        let compound_selectors = self
+            .iter_raw_match_order()
+            .as_slice()
+            .split(|x| x.is_combinator())
+            .rev();
+
+        let mut combinators_exhausted = false;
+        for compound in compound_selectors {
+            debug_assert!(!combinators_exhausted);
+
+            // https://drafts.csswg.org/cssom/#serializing-selectors
+            let first_compound = match compound.first() {
+                None => continue,
+                Some(c) => c,
+            };
+            if matches!(first_compound, Component::RelativeSelectorAnchor | Component::ImplicitScope) {
+                debug_assert!(
+                    compound.len() == 1,
+                    "RelativeSelectorAnchor/ImplicitScope should only be a simple selector"
+                );
+                combinators.next().unwrap().to_css_relative(dest)?;
+                continue;
+            }
+
+            // 1. If there is only one simple selector in the compound selectors
+            //    which is a universal selector, append the result of
+            //    serializing the universal selector to s.
+            //
+            // Check if `!compound.empty()` first--this can happen if we have
+            // something like `... > ::before`, because we store `>` and `::`
+            // both as combinators internally.
+            //
+            // If we are in this case, after we have serialized the universal
+            // selector, we skip Step 2 and continue with the algorithm.
+            let (can_elide_namespace, first_non_namespace) = match compound[0] {
+                Component::ExplicitAnyNamespace |
+                Component::ExplicitNoNamespace |
+                Component::Namespace(..) => (false, 1),
+                Component::DefaultNamespace(..) => (true, 1),
+                _ => (true, 0),
+            };
+            let mut perform_step_2 = true;
+            let next_combinator = combinators.next();
+            if first_non_namespace == compound.len() - 1 {
+                match (next_combinator, &compound[first_non_namespace]) {
+                    // We have to be careful here, because if there is a
+                    // pseudo element "combinator" there isn't really just
+                    // the one simple selector. Technically this compound
+                    // selector contains the pseudo element selector as well
+                    // -- Combinator::PseudoElement, just like
+                    // Combinator::SlotAssignment, don't exist in the
+                    // spec.
+                    (Some(Combinator::PseudoElement), _) |
+                    (Some(Combinator::SlotAssignment), _) => (),
+                    (_, &Component::ExplicitUniversalType) => {
+                        // Iterate over everything so we serialize the namespace
+                        // too.
+                        for simple in compound.iter() {
+                            simple.to_css(dest)?;
+                        }
+                        // Skip step 2, which is an "otherwise".
+                        perform_step_2 = false;
+                    },
+                    _ => (),
+                }
+            }
+
+            // 2. Otherwise, for each simple selector in the compound selectors
+            //    that is not a universal selector of which the namespace prefix
+            //    maps to a namespace that is not the default namespace
+            //    serialize the simple selector and append the result to s.
+            //
+            // See https://github.com/w3c/csswg-drafts/issues/1606, which is
+            // proposing to change this to match up with the behavior asserted
+            // in cssom/serialize-namespaced-type-selectors.html, which the
+            // following code tries to match.
+            if perform_step_2 {
+                for simple in compound.iter() {
+                    if let Component::ExplicitUniversalType = *simple {
+                        // Can't have a namespace followed by a pseudo-element
+                        // selector followed by a universal selector in the same
+                        // compound selector, so we don't have to worry about the
+                        // real namespace being in a different `compound`.
+                        if can_elide_namespace {
+                            continue;
+                        }
+                    }
+                    simple.to_css(dest)?;
+                }
+            }
+
+            // 3. If this is not the last part of the chain of the selector
+            //    append a single SPACE (U+0020), followed by the combinator
+            //    ">", "+", "~", ">>", "||", as appropriate, followed by another
+            //    single SPACE (U+0020) if the combinator was not whitespace, to
+            //    s.
+            match next_combinator {
+                Some(c) => c.to_css(dest)?,
+                None => combinators_exhausted = true,
+            };
+
+            // 4. If this is the last part of the chain of the selector and
+            //    there is a pseudo-element, append "::" followed by the name of
+            //    the pseudo-element, to s.
+            //
+            // (we handle this above)
+        }
+
+        Ok(())
+    }
+}
+
+impl Combinator {
+    fn to_css_internal<W>(&self, dest: &mut W, prefix_space: bool) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        if matches!(
+            *self,
+            Combinator::PseudoElement | Combinator::Part | Combinator::SlotAssignment
+        ) {
+            return Ok(());
+        }
+        if prefix_space {
+            dest.write_char(' ')?;
+        }
+        match *self {
+            Combinator::Child => dest.write_str("> "),
+            Combinator::Descendant => Ok(()),
+            Combinator::NextSibling => dest.write_str("+ "),
+            Combinator::LaterSibling => dest.write_str("~ "),
+            Combinator::PseudoElement | Combinator::Part | Combinator::SlotAssignment => unsafe {
+                debug_unreachable!("Already handled")
+            },
+        }
+    }
+
+    fn to_css_relative<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        self.to_css_internal(dest, false)
+    }
+}
+
+impl ToCss for Combinator {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        self.to_css_internal(dest, true)
+    }
+}
+
+impl<Impl: SelectorImpl> ToCss for Component<Impl> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        use self::Component::*;
+
+        match *self {
+            Combinator(ref c) => c.to_css(dest),
+            Slotted(ref selector) => {
+                dest.write_str("::slotted(")?;
+                selector.to_css(dest)?;
+                dest.write_char(')')
+            },
+            Part(ref part_names) => {
+                dest.write_str("::part(")?;
+                for (i, name) in part_names.iter().enumerate() {
+                    if i != 0 {
+                        dest.write_char(' ')?;
+                    }
+                    name.to_css(dest)?;
+                }
+                dest.write_char(')')
+            },
+            PseudoElement(ref p) => p.to_css(dest),
+            ID(ref s) => {
+                dest.write_char('#')?;
+                s.to_css(dest)
+            },
+            Class(ref s) => {
+                dest.write_char('.')?;
+                s.to_css(dest)
+            },
+            LocalName(ref s) => s.to_css(dest),
+            ExplicitUniversalType => dest.write_char('*'),
+
+            DefaultNamespace(_) => Ok(()),
+            ExplicitNoNamespace => dest.write_char('|'),
+            ExplicitAnyNamespace => dest.write_str("*|"),
+            Namespace(ref prefix, _) => {
+                prefix.to_css(dest)?;
+                dest.write_char('|')
+            },
+
+            AttributeInNoNamespaceExists { ref local_name, .. } => {
+                dest.write_char('[')?;
+                local_name.to_css(dest)?;
+                dest.write_char(']')
+            },
+            AttributeInNoNamespace {
+                ref local_name,
+                operator,
+                ref value,
+                case_sensitivity,
+                ..
+            } => {
+                dest.write_char('[')?;
+                local_name.to_css(dest)?;
+                operator.to_css(dest)?;
+                value.to_css(dest)?;
+                match case_sensitivity {
+                    ParsedCaseSensitivity::CaseSensitive |
+                    ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {},
+                    ParsedCaseSensitivity::AsciiCaseInsensitive => dest.write_str(" i")?,
+                    ParsedCaseSensitivity::ExplicitCaseSensitive => dest.write_str(" s")?,
+                }
+                dest.write_char(']')
+            },
+            AttributeOther(ref attr_selector) => attr_selector.to_css(dest),
+
+            // Pseudo-classes
+            Root => dest.write_str(":root"),
+            Empty => dest.write_str(":empty"),
+            Scope => dest.write_str(":scope"),
+            ParentSelector => dest.write_char('&'),
+            Host(ref selector) => {
+                dest.write_str(":host")?;
+                if let Some(ref selector) = *selector {
+                    dest.write_char('(')?;
+                    selector.to_css(dest)?;
+                    dest.write_char(')')?;
+                }
+                Ok(())
+            },
+            Nth(ref nth_data) => {
+                nth_data.write_start(dest)?;
+                if nth_data.is_function {
+                    nth_data.write_affine(dest)?;
+                    dest.write_char(')')?;
+                }
+                Ok(())
+            },
+            NthOf(ref nth_of_data) => {
+                let nth_data = nth_of_data.nth_data();
+                nth_data.write_start(dest)?;
+                debug_assert!(
+                    nth_data.is_function,
+                    "A selector must be a function to hold An+B notation"
+                );
+                nth_data.write_affine(dest)?;
+                debug_assert!(
+                    matches!(nth_data.ty, NthType::Child | NthType::LastChild),
+                    "Only :nth-child or :nth-last-child can be of a selector list"
+                );
+                debug_assert!(
+                    !nth_of_data.selectors().is_empty(),
+                    "The selector list should not be empty"
+                );
+                dest.write_str(" of ")?;
+                serialize_selector_list(nth_of_data.selectors().iter(), dest)?;
+                dest.write_char(')')
+            },
+            Is(ref list) | Where(ref list) | Negation(ref list) => {
+                match *self {
+                    Where(..) => dest.write_str(":where(")?,
+                    Is(..) => dest.write_str(":is(")?,
+                    Negation(..) => dest.write_str(":not(")?,
+                    _ => unreachable!(),
+                }
+                serialize_selector_list(list.slice().iter(), dest)?;
+                dest.write_str(")")
+            },
+            Has(ref list) => {
+                dest.write_str(":has(")?;
+                let mut first = true;
+                for RelativeSelector { ref selector, .. } in list.iter() {
+                    if !first {
+                        dest.write_str(", ")?;
+                    }
+                    first = false;
+                    selector.to_css(dest)?;
+                }
+                dest.write_str(")")
+            },
+            NonTSPseudoClass(ref pseudo) => pseudo.to_css(dest),
+            Invalid(ref css) => dest.write_str(css),
+            RelativeSelectorAnchor | ImplicitScope => Ok(()),
+        }
+    }
+}
+
+impl<Impl: SelectorImpl> ToCss for AttrSelectorWithOptionalNamespace<Impl> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        dest.write_char('[')?;
+        match self.namespace {
+            Some(NamespaceConstraint::Specific((ref prefix, _))) => {
+                prefix.to_css(dest)?;
+                dest.write_char('|')?
+            },
+            Some(NamespaceConstraint::Any) => dest.write_str("*|")?,
+            None => {},
+        }
+        self.local_name.to_css(dest)?;
+        match self.operation {
+            ParsedAttrSelectorOperation::Exists => {},
+            ParsedAttrSelectorOperation::WithValue {
+                operator,
+                case_sensitivity,
+                ref value,
+            } => {
+                operator.to_css(dest)?;
+                value.to_css(dest)?;
+                match case_sensitivity {
+                    ParsedCaseSensitivity::CaseSensitive |
+                    ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {},
+                    ParsedCaseSensitivity::AsciiCaseInsensitive => dest.write_str(" i")?,
+                    ParsedCaseSensitivity::ExplicitCaseSensitive => dest.write_str(" s")?,
+                }
+            },
+        }
+        dest.write_char(']')
+    }
+}
+
+impl<Impl: SelectorImpl> ToCss for LocalName<Impl> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        self.name.to_css(dest)
+    }
+}
+
+/// Build up a Selector.
+/// selector : simple_selector_sequence [ combinator simple_selector_sequence ]* ;
+///
+/// `Err` means invalid selector.
+fn parse_selector<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    mut state: SelectorParsingState,
+    parse_relative: ParseRelative,
+) -> Result<Selector<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    let mut builder = SelectorBuilder::default();
+
+    // Helps rewind less, but also simplifies dealing with relative combinators below.
+    input.skip_whitespace();
+
+    if parse_relative != ParseRelative::No {
+        let combinator = try_parse_combinator::<P, Impl>(input);
+        match parse_relative {
+            ParseRelative::ForHas => {
+                builder.push_simple_selector(Component::RelativeSelectorAnchor);
+                // Do we see a combinator? If so, push that. Otherwise, push a descendant
+                // combinator.
+                builder.push_combinator(combinator.unwrap_or(Combinator::Descendant));
+            },
+            ParseRelative::ForNesting | ParseRelative::ForScope => {
+                if let Ok(combinator) = combinator {
+                    let selector = match parse_relative {
+                        ParseRelative::ForHas | ParseRelative::No => unreachable!(),
+                        ParseRelative::ForNesting => Component::ParentSelector,
+                        // See https://github.com/w3c/csswg-drafts/issues/10196
+                        // Implicitly added `:scope` does not add specificity
+                        // for non-relative selectors, so do the same.
+                        ParseRelative::ForScope => Component::ImplicitScope,
+                    };
+                    builder.push_simple_selector(selector);
+                    builder.push_combinator(combinator);
+                }
+            },
+            ParseRelative::No => unreachable!(),
+        }
+    }
+    'outer_loop: loop {
+        // Parse a sequence of simple selectors.
+        let empty = parse_compound_selector(parser, &mut state, input, &mut builder)?;
+        if empty {
+            return Err(input.new_custom_error(if builder.has_combinators() {
+                SelectorParseErrorKind::DanglingCombinator
+            } else {
+                SelectorParseErrorKind::EmptySelector
+            }));
+        }
+
+        if state.intersects(SelectorParsingState::AFTER_PSEUDO) {
+            debug_assert!(state.intersects(
+                SelectorParsingState::AFTER_PSEUDO_ELEMENT |
+                    SelectorParsingState::AFTER_SLOTTED |
+                    SelectorParsingState::AFTER_PART
+            ));
+            break;
+        }
+
+        let combinator = if let Ok(c) = try_parse_combinator::<P, Impl>(input) {
+            c
+        } else {
+            break 'outer_loop;
+        };
+
+        if !state.allows_combinators() {
+            return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+        }
+
+        builder.push_combinator(combinator);
+    }
+    return Ok(Selector(builder.build(parse_relative)));
+}
+
+fn try_parse_combinator<'i, 't, P, Impl>(input: &mut CssParser<'i, 't>) -> Result<Combinator, ()> {
+    let mut any_whitespace = false;
+    loop {
+        let before_this_token = input.state();
+        match input.next_including_whitespace() {
+            Err(_e) => return Err(()),
+            Ok(&Token::WhiteSpace(_)) => any_whitespace = true,
+            Ok(&Token::Delim('>')) => {
+                return Ok(Combinator::Child);
+            },
+            Ok(&Token::Delim('+')) => {
+                return Ok(Combinator::NextSibling);
+            },
+            Ok(&Token::Delim('~')) => {
+                return Ok(Combinator::LaterSibling);
+            },
+            Ok(_) => {
+                input.reset(&before_this_token);
+                if any_whitespace {
+                    return Ok(Combinator::Descendant);
+                } else {
+                    return Err(());
+                }
+            },
+        }
+    }
+}
+
+/// * `Err(())`: Invalid selector, abort
+/// * `Ok(false)`: Not a type selector, could be something else. `input` was not consumed.
+/// * `Ok(true)`: Length 0 (`*|*`), 1 (`*|E` or `ns|*`) or 2 (`|E` or `ns|E`)
+fn parse_type_selector<'i, 't, P, Impl, S>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+    sink: &mut S,
+) -> Result<bool, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+    S: Push<Component<Impl>>,
+{
+    match parse_qualified_name(parser, input, /* in_attr_selector = */ false) {
+        Err(ParseError {
+            kind: ParseErrorKind::Basic(BasicParseErrorKind::EndOfInput),
+            ..
+        }) |
+        Ok(OptionalQName::None(_)) => Ok(false),
+        Ok(OptionalQName::Some(namespace, local_name)) => {
+            if state.intersects(SelectorParsingState::AFTER_PSEUDO) {
+                return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+            }
+            match namespace {
+                QNamePrefix::ImplicitAnyNamespace => {},
+                QNamePrefix::ImplicitDefaultNamespace(url) => {
+                    sink.push(Component::DefaultNamespace(url))
+                },
+                QNamePrefix::ExplicitNamespace(prefix, url) => {
+                    sink.push(match parser.default_namespace() {
+                        Some(ref default_url) if url == *default_url => {
+                            Component::DefaultNamespace(url)
+                        },
+                        _ => Component::Namespace(prefix, url),
+                    })
+                },
+                QNamePrefix::ExplicitNoNamespace => sink.push(Component::ExplicitNoNamespace),
+                QNamePrefix::ExplicitAnyNamespace => {
+                    match parser.default_namespace() {
+                        // Element type selectors that have no namespace
+                        // component (no namespace separator) represent elements
+                        // without regard to the element's namespace (equivalent
+                        // to "*|") unless a default namespace has been declared
+                        // for namespaced selectors (e.g. in CSS, in the style
+                        // sheet). If a default namespace has been declared,
+                        // such selectors will represent only elements in the
+                        // default namespace.
+                        // -- Selectors § 6.1.1
+                        // So we'll have this act the same as the
+                        // QNamePrefix::ImplicitAnyNamespace case.
+                        None => {},
+                        Some(_) => sink.push(Component::ExplicitAnyNamespace),
+                    }
+                },
+                QNamePrefix::ImplicitNoNamespace => {
+                    unreachable!() // Not returned with in_attr_selector = false
+                },
+            }
+            match local_name {
+                Some(name) => sink.push(Component::LocalName(LocalName {
+                    lower_name: to_ascii_lowercase(&name).as_ref().into(),
+                    name: name.as_ref().into(),
+                })),
+                None => sink.push(Component::ExplicitUniversalType),
+            }
+            Ok(true)
+        },
+        Err(e) => Err(e),
+    }
+}
+
+#[derive(Debug)]
+enum SimpleSelectorParseResult<Impl: SelectorImpl> {
+    SimpleSelector(Component<Impl>),
+    PseudoElement(Impl::PseudoElement),
+    SlottedPseudo(Selector<Impl>),
+    PartPseudo(Box<[Impl::Identifier]>),
+}
+
+#[derive(Debug)]
+enum QNamePrefix<Impl: SelectorImpl> {
+    ImplicitNoNamespace,                          // `foo` in attr selectors
+    ImplicitAnyNamespace,                         // `foo` in type selectors, without a default ns
+    ImplicitDefaultNamespace(Impl::NamespaceUrl), // `foo` in type selectors, with a default ns
+    ExplicitNoNamespace,                          // `|foo`
+    ExplicitAnyNamespace,                         // `*|foo`
+    ExplicitNamespace(Impl::NamespacePrefix, Impl::NamespaceUrl), // `prefix|foo`
+}
+
+enum OptionalQName<'i, Impl: SelectorImpl> {
+    Some(QNamePrefix<Impl>, Option<CowRcStr<'i>>),
+    None(Token<'i>),
+}
+
+/// * `Err(())`: Invalid selector, abort
+/// * `Ok(None(token))`: Not a simple selector, could be something else. `input` was not consumed,
+///                      but the token is still returned.
+/// * `Ok(Some(namespace, local_name))`: `None` for the local name means a `*` universal selector
+fn parse_qualified_name<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    in_attr_selector: bool,
+) -> Result<OptionalQName<'i, Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    let default_namespace = |local_name| {
+        let namespace = match parser.default_namespace() {
+            Some(url) => QNamePrefix::ImplicitDefaultNamespace(url),
+            None => QNamePrefix::ImplicitAnyNamespace,
+        };
+        Ok(OptionalQName::Some(namespace, local_name))
+    };
+
+    let explicit_namespace = |input: &mut CssParser<'i, 't>, namespace| {
+        let location = input.current_source_location();
+        match input.next_including_whitespace() {
+            Ok(&Token::Delim('*')) if !in_attr_selector => Ok(OptionalQName::Some(namespace, None)),
+            Ok(&Token::Ident(ref local_name)) => {
+                Ok(OptionalQName::Some(namespace, Some(local_name.clone())))
+            },
+            Ok(t) if in_attr_selector => {
+                let e = SelectorParseErrorKind::InvalidQualNameInAttr(t.clone());
+                Err(location.new_custom_error(e))
+            },
+            Ok(t) => Err(location.new_custom_error(
+                SelectorParseErrorKind::ExplicitNamespaceUnexpectedToken(t.clone()),
+            )),
+            Err(e) => Err(e.into()),
+        }
+    };
+
+    let start = input.state();
+    match input.next_including_whitespace() {
+        Ok(Token::Ident(value)) => {
+            let value = value.clone();
+            let after_ident = input.state();
+            match input.next_including_whitespace() {
+                Ok(&Token::Delim('|')) => {
+                    let prefix = value.as_ref().into();
+                    let result = parser.namespace_for_prefix(&prefix);
+                    let url = result.ok_or(
+                        after_ident
+                            .source_location()
+                            .new_custom_error(SelectorParseErrorKind::ExpectedNamespace(value)),
+                    )?;
+                    explicit_namespace(input, QNamePrefix::ExplicitNamespace(prefix, url))
+                },
+                _ => {
+                    input.reset(&after_ident);
+                    if in_attr_selector {
+                        Ok(OptionalQName::Some(
+                            QNamePrefix::ImplicitNoNamespace,
+                            Some(value),
+                        ))
+                    } else {
+                        default_namespace(Some(value))
+                    }
+                },
+            }
+        },
+        Ok(Token::Delim('*')) => {
+            let after_star = input.state();
+            match input.next_including_whitespace() {
+                Ok(&Token::Delim('|')) => {
+                    explicit_namespace(input, QNamePrefix::ExplicitAnyNamespace)
+                },
+                _ if !in_attr_selector => {
+                    input.reset(&after_star);
+                    default_namespace(None)
+                },
+                result => {
+                    let t = result?;
+                    Err(after_star
+                        .source_location()
+                        .new_custom_error(SelectorParseErrorKind::ExpectedBarInAttr(t.clone())))
+                },
+            }
+        },
+        Ok(Token::Delim('|')) => explicit_namespace(input, QNamePrefix::ExplicitNoNamespace),
+        Ok(t) => {
+            let t = t.clone();
+            input.reset(&start);
+            Ok(OptionalQName::None(t))
+        },
+        Err(e) => {
+            input.reset(&start);
+            Err(e.into())
+        },
+    }
+}
+
+fn parse_attribute_selector<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    let namespace;
+    let local_name;
+
+    input.skip_whitespace();
+
+    match parse_qualified_name(parser, input, /* in_attr_selector = */ true)? {
+        OptionalQName::None(t) => {
+            return Err(input.new_custom_error(
+                SelectorParseErrorKind::NoQualifiedNameInAttributeSelector(t),
+            ));
+        },
+        OptionalQName::Some(_, None) => unreachable!(),
+        OptionalQName::Some(ns, Some(ln)) => {
+            local_name = ln;
+            namespace = match ns {
+                QNamePrefix::ImplicitNoNamespace | QNamePrefix::ExplicitNoNamespace => None,
+                QNamePrefix::ExplicitNamespace(prefix, url) => {
+                    Some(NamespaceConstraint::Specific((prefix, url)))
+                },
+                QNamePrefix::ExplicitAnyNamespace => Some(NamespaceConstraint::Any),
+                QNamePrefix::ImplicitAnyNamespace | QNamePrefix::ImplicitDefaultNamespace(_) => {
+                    unreachable!() // Not returned with in_attr_selector = true
+                },
+            }
+        },
+    }
+
+    let location = input.current_source_location();
+    let operator = match input.next() {
+        // [foo]
+        Err(_) => {
+            let local_name_lower = to_ascii_lowercase(&local_name).as_ref().into();
+            let local_name = local_name.as_ref().into();
+            if let Some(namespace) = namespace {
+                return Ok(Component::AttributeOther(Box::new(
+                    AttrSelectorWithOptionalNamespace {
+                        namespace: Some(namespace),
+                        local_name,
+                        local_name_lower,
+                        operation: ParsedAttrSelectorOperation::Exists,
+                    },
+                )));
+            } else {
+                return Ok(Component::AttributeInNoNamespaceExists {
+                    local_name,
+                    local_name_lower,
+                });
+            }
+        },
+
+        // [foo=bar]
+        Ok(&Token::Delim('=')) => AttrSelectorOperator::Equal,
+        // [foo~=bar]
+        Ok(&Token::IncludeMatch) => AttrSelectorOperator::Includes,
+        // [foo|=bar]
+        Ok(&Token::DashMatch) => AttrSelectorOperator::DashMatch,
+        // [foo^=bar]
+        Ok(&Token::PrefixMatch) => AttrSelectorOperator::Prefix,
+        // [foo*=bar]
+        Ok(&Token::SubstringMatch) => AttrSelectorOperator::Substring,
+        // [foo$=bar]
+        Ok(&Token::SuffixMatch) => AttrSelectorOperator::Suffix,
+        Ok(t) => {
+            return Err(location.new_custom_error(
+                SelectorParseErrorKind::UnexpectedTokenInAttributeSelector(t.clone()),
+            ));
+        },
+    };
+
+    let value = match input.expect_ident_or_string() {
+        Ok(t) => t.clone(),
+        Err(BasicParseError {
+            kind: BasicParseErrorKind::UnexpectedToken(t),
+            location,
+        }) => return Err(location.new_custom_error(SelectorParseErrorKind::BadValueInAttr(t))),
+        Err(e) => return Err(e.into()),
+    };
+
+    let attribute_flags = parse_attribute_flags(input)?;
+    let value = value.as_ref().into();
+    let local_name_lower;
+    let local_name_is_ascii_lowercase;
+    let case_sensitivity;
+    {
+        let local_name_lower_cow = to_ascii_lowercase(&local_name);
+        case_sensitivity =
+            attribute_flags.to_case_sensitivity(local_name_lower_cow.as_ref(), namespace.is_some());
+        local_name_lower = local_name_lower_cow.as_ref().into();
+        local_name_is_ascii_lowercase = matches!(local_name_lower_cow, Cow::Borrowed(..));
+    }
+    let local_name = local_name.as_ref().into();
+    if namespace.is_some() || !local_name_is_ascii_lowercase {
+        Ok(Component::AttributeOther(Box::new(
+            AttrSelectorWithOptionalNamespace {
+                namespace,
+                local_name,
+                local_name_lower,
+                operation: ParsedAttrSelectorOperation::WithValue {
+                    operator,
+                    case_sensitivity,
+                    value,
+                },
+            },
+        )))
+    } else {
+        Ok(Component::AttributeInNoNamespace {
+            local_name,
+            operator,
+            value,
+            case_sensitivity,
+        })
+    }
+}
+
+/// An attribute selector can have 's' or 'i' as flags, or no flags at all.
+enum AttributeFlags {
+    // Matching should be case-sensitive ('s' flag).
+    CaseSensitive,
+    // Matching should be case-insensitive ('i' flag).
+    AsciiCaseInsensitive,
+    // No flags.  Matching behavior depends on the name of the attribute.
+    CaseSensitivityDependsOnName,
+}
+
+impl AttributeFlags {
+    fn to_case_sensitivity(self, local_name: &str, have_namespace: bool) -> ParsedCaseSensitivity {
+        match self {
+            AttributeFlags::CaseSensitive => ParsedCaseSensitivity::ExplicitCaseSensitive,
+            AttributeFlags::AsciiCaseInsensitive => ParsedCaseSensitivity::AsciiCaseInsensitive,
+            AttributeFlags::CaseSensitivityDependsOnName => {
+                if !have_namespace &&
+                    include!(concat!(
+                        env!("OUT_DIR"),
+                        "/ascii_case_insensitive_html_attributes.rs"
+                    ))
+                    .contains(local_name)
+                {
+                    ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument
+                } else {
+                    ParsedCaseSensitivity::CaseSensitive
+                }
+            },
+        }
+    }
+}
+
+fn parse_attribute_flags<'i, 't>(
+    input: &mut CssParser<'i, 't>,
+) -> Result<AttributeFlags, BasicParseError<'i>> {
+    let location = input.current_source_location();
+    let token = match input.next() {
+        Ok(t) => t,
+        Err(..) => {
+            // Selectors spec says language-defined; HTML says it depends on the
+            // exact attribute name.
+            return Ok(AttributeFlags::CaseSensitivityDependsOnName);
+        },
+    };
+
+    let ident = match *token {
+        Token::Ident(ref i) => i,
+        ref other => return Err(location.new_basic_unexpected_token_error(other.clone())),
+    };
+
+    Ok(match_ignore_ascii_case! {
+        ident,
+        "i" => AttributeFlags::AsciiCaseInsensitive,
+        "s" => AttributeFlags::CaseSensitive,
+        _ => return Err(location.new_basic_unexpected_token_error(token.clone())),
+    })
+}
+
+/// Level 3: Parse **one** simple_selector.  (Though we might insert a second
+/// implied "<defaultns>|*" type selector.)
+fn parse_negation<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    let list = SelectorList::parse_with_state(
+        parser,
+        input,
+        state |
+            SelectorParsingState::SKIP_DEFAULT_NAMESPACE |
+            SelectorParsingState::DISALLOW_PSEUDOS,
+        ForgivingParsing::No,
+        ParseRelative::No,
+    )?;
+
+    Ok(Component::Negation(list))
+}
+
+/// simple_selector_sequence
+/// : [ type_selector | universal ] [ HASH | class | attrib | pseudo | negation ]*
+/// | [ HASH | class | attrib | pseudo | negation ]+
+///
+/// `Err(())` means invalid selector.
+/// `Ok(true)` is an empty selector
+fn parse_compound_selector<'i, 't, P, Impl>(
+    parser: &P,
+    state: &mut SelectorParsingState,
+    input: &mut CssParser<'i, 't>,
+    builder: &mut SelectorBuilder<Impl>,
+) -> Result<bool, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    input.skip_whitespace();
+
+    let mut empty = true;
+    if parse_type_selector(parser, input, *state, builder)? {
+        empty = false;
+    }
+
+    loop {
+        let result = match parse_one_simple_selector(parser, input, *state)? {
+            None => break,
+            Some(result) => result,
+        };
+
+        if empty {
+            if let Some(url) = parser.default_namespace() {
+                // If there was no explicit type selector, but there is a
+                // default namespace, there is an implicit "<defaultns>|*" type
+                // selector. Except for :host() or :not() / :is() / :where(),
+                // where we ignore it.
+                //
+                // https://drafts.csswg.org/css-scoping/#host-element-in-tree:
+                //
+                //     When considered within its own shadow trees, the shadow
+                //     host is featureless. Only the :host, :host(), and
+                //     :host-context() pseudo-classes are allowed to match it.
+                //
+                // https://drafts.csswg.org/selectors-4/#featureless:
+                //
+                //     A featureless element does not match any selector at all,
+                //     except those it is explicitly defined to match. If a
+                //     given selector is allowed to match a featureless element,
+                //     it must do so while ignoring the default namespace.
+                //
+                // https://drafts.csswg.org/selectors-4/#matches
+                //
+                //     Default namespace declarations do not affect the compound
+                //     selector representing the subject of any selector within
+                //     a :is() pseudo-class, unless that compound selector
+                //     contains an explicit universal selector or type selector.
+                //
+                //     (Similar quotes for :where() / :not())
+                //
+                let ignore_default_ns = state
+                    .intersects(SelectorParsingState::SKIP_DEFAULT_NAMESPACE) ||
+                    matches!(
+                        result,
+                        SimpleSelectorParseResult::SimpleSelector(Component::Host(..))
+                    );
+                if !ignore_default_ns {
+                    builder.push_simple_selector(Component::DefaultNamespace(url));
+                }
+            }
+        }
+
+        empty = false;
+
+        match result {
+            SimpleSelectorParseResult::SimpleSelector(s) => {
+                builder.push_simple_selector(s);
+            },
+            SimpleSelectorParseResult::PartPseudo(part_names) => {
+                state.insert(SelectorParsingState::AFTER_PART);
+                builder.push_combinator(Combinator::Part);
+                builder.push_simple_selector(Component::Part(part_names));
+            },
+            SimpleSelectorParseResult::SlottedPseudo(selector) => {
+                state.insert(SelectorParsingState::AFTER_SLOTTED);
+                builder.push_combinator(Combinator::SlotAssignment);
+                builder.push_simple_selector(Component::Slotted(selector));
+            },
+            SimpleSelectorParseResult::PseudoElement(p) => {
+                state.insert(SelectorParsingState::AFTER_PSEUDO_ELEMENT);
+                if !p.accepts_state_pseudo_classes() {
+                    state.insert(SelectorParsingState::AFTER_NON_STATEFUL_PSEUDO_ELEMENT);
+                }
+                if p.is_in_pseudo_element_tree() {
+                    state.insert(SelectorParsingState::IN_PSEUDO_ELEMENT_TREE);
+                }
+                builder.push_combinator(Combinator::PseudoElement);
+                builder.push_simple_selector(Component::PseudoElement(p));
+            },
+        }
+    }
+    Ok(empty)
+}
+
+fn parse_is_where<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+    component: impl FnOnce(SelectorList<Impl>) -> Component<Impl>,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    debug_assert!(parser.parse_is_and_where());
+    // https://drafts.csswg.org/selectors/#matches-pseudo:
+    //
+    //     Pseudo-elements cannot be represented by the matches-any
+    //     pseudo-class; they are not valid within :is().
+    //
+    let inner = SelectorList::parse_with_state(
+        parser,
+        input,
+        state |
+            SelectorParsingState::SKIP_DEFAULT_NAMESPACE |
+            SelectorParsingState::DISALLOW_PSEUDOS,
+        ForgivingParsing::Yes,
+        ParseRelative::No,
+    )?;
+    Ok(component(inner))
+}
+
+fn parse_has<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    debug_assert!(parser.parse_has());
+    if state.intersects(SelectorParsingState::DISALLOW_RELATIVE_SELECTOR) {
+        return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+    }
+    // Nested `:has()` is disallowed, mark it as such.
+    // Note: The spec defines ":has-allowed pseudo-element," but there's no
+    // pseudo-element defined as such at the moment.
+    // https://w3c.github.io/csswg-drafts/selectors-4/#has-allowed-pseudo-element
+    let inner = SelectorList::parse_with_state(
+        parser,
+        input,
+        state |
+            SelectorParsingState::SKIP_DEFAULT_NAMESPACE |
+            SelectorParsingState::DISALLOW_PSEUDOS |
+            SelectorParsingState::DISALLOW_RELATIVE_SELECTOR,
+        ForgivingParsing::No,
+        ParseRelative::ForHas,
+    )?;
+    Ok(Component::Has(RelativeSelector::from_selector_list(inner)))
+}
+
+fn parse_functional_pseudo_class<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    name: CowRcStr<'i>,
+    state: SelectorParsingState,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    match_ignore_ascii_case! { &name,
+        "nth-child" => return parse_nth_pseudo_class(parser, input, state, NthType::Child),
+        "nth-of-type" => return parse_nth_pseudo_class(parser, input, state, NthType::OfType),
+        "nth-last-child" => return parse_nth_pseudo_class(parser, input, state, NthType::LastChild),
+        "nth-last-of-type" => return parse_nth_pseudo_class(parser, input, state, NthType::LastOfType),
+        "is" if parser.parse_is_and_where() => return parse_is_where(parser, input, state, Component::Is),
+        "where" if parser.parse_is_and_where() => return parse_is_where(parser, input, state, Component::Where),
+        "has" if parser.parse_has() => return parse_has(parser, input, state),
+        "host" => {
+            if !state.allows_tree_structural_pseudo_classes() {
+                return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+            }
+            return Ok(Component::Host(Some(parse_inner_compound_selector(parser, input, state)?)));
+        },
+        "not" => {
+            return parse_negation(parser, input, state)
+        },
+        _ => {}
+    }
+
+    if parser.parse_is_and_where() && parser.is_is_alias(&name) {
+        return parse_is_where(parser, input, state, Component::Is);
+    }
+
+    if state.intersects(SelectorParsingState::AFTER_PSEUDO_ELEMENT | SelectorParsingState::AFTER_SLOTTED) {
+        return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+    }
+
+    let after_part = state.intersects(SelectorParsingState::AFTER_PART);
+    P::parse_non_ts_functional_pseudo_class(parser, name, input, after_part).map(Component::NonTSPseudoClass)
+}
+
+fn parse_nth_pseudo_class<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+    ty: NthType,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    if !state.allows_tree_structural_pseudo_classes() {
+        return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+    }
+    let (a, b) = parse_nth(input)?;
+    let nth_data = NthSelectorData {
+        ty,
+        is_function: true,
+        a,
+        b,
+    };
+    if !parser.parse_nth_child_of() || ty.is_of_type() {
+        return Ok(Component::Nth(nth_data));
+    }
+
+    // Try to parse "of <selector-list>".
+    if input.try_parse(|i| i.expect_ident_matching("of")).is_err() {
+        return Ok(Component::Nth(nth_data));
+    }
+    // Whitespace between "of" and the selector list is optional
+    // https://github.com/w3c/csswg-drafts/issues/8285
+    let selectors = SelectorList::parse_with_state(
+        parser,
+        input,
+        state |
+            SelectorParsingState::SKIP_DEFAULT_NAMESPACE |
+            SelectorParsingState::DISALLOW_PSEUDOS,
+        ForgivingParsing::No,
+        ParseRelative::No,
+    )?;
+    Ok(Component::NthOf(NthOfSelectorData::new(
+        &nth_data,
+        selectors.slice().iter().cloned(),
+    )))
+}
+
+/// Returns whether the name corresponds to a CSS2 pseudo-element that
+/// can be specified with the single colon syntax (in addition to the
+/// double-colon syntax, which can be used for all pseudo-elements).
+fn is_css2_pseudo_element(name: &str) -> bool {
+    // ** Do not add to this list! **
+    match_ignore_ascii_case! { name,
+        "before" | "after" | "first-line" | "first-letter" => true,
+        _ => false,
+    }
+}
+
+/// Parse a simple selector other than a type selector.
+///
+/// * `Err(())`: Invalid selector, abort
+/// * `Ok(None)`: Not a simple selector, could be something else. `input` was not consumed.
+/// * `Ok(Some(_))`: Parsed a simple selector or pseudo-element
+fn parse_one_simple_selector<'i, 't, P, Impl>(
+    parser: &P,
+    input: &mut CssParser<'i, 't>,
+    state: SelectorParsingState,
+) -> Result<Option<SimpleSelectorParseResult<Impl>>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    let start = input.state();
+    let token = match input.next_including_whitespace().map(|t| t.clone()) {
+        Ok(t) => t,
+        Err(..) => {
+            input.reset(&start);
+            return Ok(None);
+        },
+    };
+
+    Ok(Some(match token {
+        Token::IDHash(id) => {
+            if state.intersects(SelectorParsingState::AFTER_PSEUDO) {
+                return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+            }
+            let id = Component::ID(id.as_ref().into());
+            SimpleSelectorParseResult::SimpleSelector(id)
+        },
+        Token::Delim(delim) if delim == '.' || (delim == '&' && parser.parse_parent_selector()) => {
+            if state.intersects(SelectorParsingState::AFTER_PSEUDO) {
+                return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+            }
+            let location = input.current_source_location();
+            SimpleSelectorParseResult::SimpleSelector(if delim == '&' {
+                Component::ParentSelector
+            } else {
+                let class = match *input.next_including_whitespace()? {
+                    Token::Ident(ref class) => class,
+                    ref t => {
+                        let e = SelectorParseErrorKind::ClassNeedsIdent(t.clone());
+                        return Err(location.new_custom_error(e));
+                    },
+                };
+                Component::Class(class.as_ref().into())
+            })
+        },
+        Token::SquareBracketBlock => {
+            if state.intersects(SelectorParsingState::AFTER_PSEUDO) {
+                return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+            }
+            let attr = input.parse_nested_block(|input| parse_attribute_selector(parser, input))?;
+            SimpleSelectorParseResult::SimpleSelector(attr)
+        },
+        Token::Colon => {
+            let location = input.current_source_location();
+            let (is_single_colon, next_token) = match input.next_including_whitespace()?.clone() {
+                Token::Colon => (false, input.next_including_whitespace()?.clone()),
+                t => (true, t),
+            };
+            let (name, is_functional) = match next_token {
+                Token::Ident(name) => (name, false),
+                Token::Function(name) => (name, true),
+                t => {
+                    let e = SelectorParseErrorKind::PseudoElementExpectedIdent(t);
+                    return Err(input.new_custom_error(e));
+                },
+            };
+            let is_pseudo_element = !is_single_colon || is_css2_pseudo_element(&name);
+            if is_pseudo_element {
+                if !state.allows_pseudos() {
+                    return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+                }
+                let pseudo_element = if is_functional {
+                    if P::parse_part(parser) && name.eq_ignore_ascii_case("part") {
+                        if !state.allows_part() {
+                            return Err(
+                                input.new_custom_error(SelectorParseErrorKind::InvalidState)
+                            );
+                        }
+                        let names = input.parse_nested_block(|input| {
+                            let mut result = Vec::with_capacity(1);
+                            result.push(input.expect_ident()?.as_ref().into());
+                            while !input.is_exhausted() {
+                                result.push(input.expect_ident()?.as_ref().into());
+                            }
+                            Ok(result.into_boxed_slice())
+                        })?;
+                        return Ok(Some(SimpleSelectorParseResult::PartPseudo(names)));
+                    }
+                    if P::parse_slotted(parser) && name.eq_ignore_ascii_case("slotted") {
+                        if !state.allows_slotted() {
+                            return Err(
+                                input.new_custom_error(SelectorParseErrorKind::InvalidState)
+                            );
+                        }
+                        let selector = input.parse_nested_block(|input| {
+                            parse_inner_compound_selector(parser, input, state)
+                        })?;
+                        return Ok(Some(SimpleSelectorParseResult::SlottedPseudo(selector)));
+                    }
+                    input.parse_nested_block(|input| {
+                        P::parse_functional_pseudo_element(parser, name, input)
+                    })?
+                } else {
+                    P::parse_pseudo_element(parser, location, name)?
+                };
+
+                if state.intersects(SelectorParsingState::AFTER_SLOTTED) &&
+                    !pseudo_element.valid_after_slotted()
+                {
+                    return Err(input.new_custom_error(SelectorParseErrorKind::InvalidState));
+                }
+                SimpleSelectorParseResult::PseudoElement(pseudo_element)
+            } else {
+                let pseudo_class = if is_functional {
+                    input.parse_nested_block(|input| {
+                        parse_functional_pseudo_class(parser, input, name, state)
+                    })?
+                } else {
+                    parse_simple_pseudo_class(parser, location, name, state)?
+                };
+                SimpleSelectorParseResult::SimpleSelector(pseudo_class)
+            }
+        },
+        _ => {
+            input.reset(&start);
+            return Ok(None);
+        },
+    }))
+}
+
+fn parse_simple_pseudo_class<'i, P, Impl>(
+    parser: &P,
+    location: SourceLocation,
+    name: CowRcStr<'i>,
+    state: SelectorParsingState,
+) -> Result<Component<Impl>, ParseError<'i, P::Error>>
+where
+    P: Parser<'i, Impl = Impl>,
+    Impl: SelectorImpl,
+{
+    if !state.allows_non_functional_pseudo_classes() {
+        return Err(location.new_custom_error(SelectorParseErrorKind::InvalidState));
+    }
+
+    if state.allows_tree_structural_pseudo_classes() {
+        // If a descendant pseudo of a pseudo-element root has no other siblings, then :only-child
+        // matches that pseudo. Note that we don't accept other tree structural pseudo classes in
+        // this case (to match other browsers). And the spec mentions only `:only-child` as well.
+        // https://drafts.csswg.org/css-view-transitions-1/#pseudo-root
+        if state.allows_only_child_pseudo_class_only() {
+            if name.eq_ignore_ascii_case("only-child") {
+                return Ok(Component::Nth(NthSelectorData::only(/* of_type = */ false)));
+            }
+            // Other non-functional pseudo classes are not allowed.
+            // FIXME: Perhaps we can refactor this, e.g. distinguish tree-structural pseudo classes
+            // from other non-ts pseudo classes. Otherwise, this special case looks weird.
+            return Err(location.new_custom_error(SelectorParseErrorKind::InvalidState));
+        }
+
+        match_ignore_ascii_case! { &name,
+            "first-child" => return Ok(Component::Nth(NthSelectorData::first(/* of_type = */ false))),
+            "last-child" => return Ok(Component::Nth(NthSelectorData::last(/* of_type = */ false))),
+            "only-child" => return Ok(Component::Nth(NthSelectorData::only(/* of_type = */ false))),
+            "root" => return Ok(Component::Root),
+            "empty" => return Ok(Component::Empty),
+            "scope" => return Ok(Component::Scope),
+            "host" if P::parse_host(parser) => return Ok(Component::Host(None)),
+            "first-of-type" => return Ok(Component::Nth(NthSelectorData::first(/* of_type = */ true))),
+            "last-of-type" => return Ok(Component::Nth(NthSelectorData::last(/* of_type = */ true))),
+            "only-of-type" => return Ok(Component::Nth(NthSelectorData::only(/* of_type = */ true))),
+            _ => {},
+        }
+    }
+
+    let pseudo_class = P::parse_non_ts_pseudo_class(parser, location, name)?;
+    if state.intersects(SelectorParsingState::AFTER_PSEUDO_ELEMENT) &&
+        !pseudo_class.is_user_action_state()
+    {
+        return Err(location.new_custom_error(SelectorParseErrorKind::InvalidState));
+    }
+    Ok(Component::NonTSPseudoClass(pseudo_class))
+}
+
+// NB: pub module in order to access the DummyParser
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+    use crate::builder::SelectorFlags;
+    use crate::parser;
+    use cssparser::{serialize_identifier, Parser as CssParser, ParserInput, ToCss};
+    use std::collections::HashMap;
+    use std::fmt;
+
+    #[derive(Clone, Debug, Eq, PartialEq)]
+    pub enum PseudoClass {
+        Hover,
+        Active,
+        Lang(String),
+    }
+
+    #[derive(Clone, Debug, Eq, PartialEq)]
+    pub enum PseudoElement {
+        Before,
+        After,
+        Highlight(String),
+    }
+
+    impl parser::PseudoElement for PseudoElement {
+        type Impl = DummySelectorImpl;
+
+        fn accepts_state_pseudo_classes(&self) -> bool {
+            true
+        }
+
+        fn valid_after_slotted(&self) -> bool {
+            true
+        }
+    }
+
+    impl parser::NonTSPseudoClass for PseudoClass {
+        type Impl = DummySelectorImpl;
+
+        #[inline]
+        fn is_active_or_hover(&self) -> bool {
+            matches!(*self, PseudoClass::Active | PseudoClass::Hover)
+        }
+
+        #[inline]
+        fn is_user_action_state(&self) -> bool {
+            self.is_active_or_hover()
+        }
+    }
+
+    impl ToCss for PseudoClass {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+        where
+            W: fmt::Write,
+        {
+            match *self {
+                PseudoClass::Hover => dest.write_str(":hover"),
+                PseudoClass::Active => dest.write_str(":active"),
+                PseudoClass::Lang(ref lang) => {
+                    dest.write_str(":lang(")?;
+                    serialize_identifier(lang, dest)?;
+                    dest.write_char(')')
+                },
+            }
+        }
+    }
+
+    impl ToCss for PseudoElement {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+        where
+            W: fmt::Write,
+        {
+            match *self {
+                PseudoElement::Before => dest.write_str("::before"),
+                PseudoElement::After => dest.write_str("::after"),
+                PseudoElement::Highlight(ref name) => {
+                    dest.write_str("::highlight(")?;
+                    serialize_identifier(&name, dest)?;
+                    dest.write_char(')')
+                },
+            }
+        }
+    }
+
+    #[derive(Clone, Debug, PartialEq)]
+    pub struct DummySelectorImpl;
+
+    #[derive(Default)]
+    pub struct DummyParser {
+        default_ns: Option<DummyAtom>,
+        ns_prefixes: HashMap<DummyAtom, DummyAtom>,
+    }
+
+    impl DummyParser {
+        fn default_with_namespace(default_ns: DummyAtom) -> DummyParser {
+            DummyParser {
+                default_ns: Some(default_ns),
+                ns_prefixes: Default::default(),
+            }
+        }
+    }
+
+    impl SelectorImpl for DummySelectorImpl {
+        type ExtraMatchingData<'a> = std::marker::PhantomData<&'a ()>;
+        type AttrValue = DummyAttrValue;
+        type Identifier = DummyAtom;
+        type LocalName = DummyAtom;
+        type NamespaceUrl = DummyAtom;
+        type NamespacePrefix = DummyAtom;
+        type BorrowedLocalName = DummyAtom;
+        type BorrowedNamespaceUrl = DummyAtom;
+        type NonTSPseudoClass = PseudoClass;
+        type PseudoElement = PseudoElement;
+    }
+
+    #[derive(Clone, Debug, Default, Eq, Hash, PartialEq)]
+    pub struct DummyAttrValue(String);
+
+    impl ToCss for DummyAttrValue {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+        where
+            W: fmt::Write,
+        {
+            use std::fmt::Write;
+
+            dest.write_char('"')?;
+            write!(cssparser::CssStringWriter::new(dest), "{}", &self.0)?;
+            dest.write_char('"')
+        }
+    }
+
+    impl<'a> From<&'a str> for DummyAttrValue {
+        fn from(string: &'a str) -> Self {
+            Self(string.into())
+        }
+    }
+
+    #[derive(Clone, Debug, Default, Eq, Hash, PartialEq)]
+    pub struct DummyAtom(String);
+
+    impl ToCss for DummyAtom {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+        where
+            W: fmt::Write,
+        {
+            serialize_identifier(&self.0, dest)
+        }
+    }
+
+    impl From<String> for DummyAtom {
+        fn from(string: String) -> Self {
+            DummyAtom(string)
+        }
+    }
+
+    impl<'a> From<&'a str> for DummyAtom {
+        fn from(string: &'a str) -> Self {
+            DummyAtom(string.into())
+        }
+    }
+
+    impl PrecomputedHash for DummyAtom {
+        fn precomputed_hash(&self) -> u32 {
+            self.0.as_ptr() as u32
+        }
+    }
+
+    impl<'i> Parser<'i> for DummyParser {
+        type Impl = DummySelectorImpl;
+        type Error = SelectorParseErrorKind<'i>;
+
+        fn parse_slotted(&self) -> bool {
+            true
+        }
+
+        fn parse_nth_child_of(&self) -> bool {
+            true
+        }
+
+        fn parse_is_and_where(&self) -> bool {
+            true
+        }
+
+        fn parse_has(&self) -> bool {
+            true
+        }
+
+        fn parse_parent_selector(&self) -> bool {
+            true
+        }
+
+        fn parse_part(&self) -> bool {
+            true
+        }
+
+        fn parse_host(&self) -> bool {
+            true
+        }
+
+        fn parse_non_ts_pseudo_class(
+            &self,
+            location: SourceLocation,
+            name: CowRcStr<'i>,
+        ) -> Result<PseudoClass, SelectorParseError<'i>> {
+            match_ignore_ascii_case! { &name,
+                "hover" => return Ok(PseudoClass::Hover),
+                "active" => return Ok(PseudoClass::Active),
+                _ => {}
+            }
+            Err(
+                location.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                    name,
+                )),
+            )
+        }
+
+        fn parse_non_ts_functional_pseudo_class<'t>(
+            &self,
+            name: CowRcStr<'i>,
+            parser: &mut CssParser<'i, 't>,
+            after_part: bool,
+        ) -> Result<PseudoClass, SelectorParseError<'i>> {
+            match_ignore_ascii_case! { &name,
+                "lang" if !after_part => {
+                    let lang = parser.expect_ident_or_string()?.as_ref().to_owned();
+                    return Ok(PseudoClass::Lang(lang));
+                },
+                _ => {}
+            }
+            Err(
+                parser.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                    name,
+                )),
+            )
+        }
+
+        fn parse_pseudo_element(
+            &self,
+            location: SourceLocation,
+            name: CowRcStr<'i>,
+        ) -> Result<PseudoElement, SelectorParseError<'i>> {
+            match_ignore_ascii_case! { &name,
+                "before" => return Ok(PseudoElement::Before),
+                "after" => return Ok(PseudoElement::After),
+                _ => {}
+            }
+            Err(
+                location.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                    name,
+                )),
+            )
+        }
+
+        fn parse_functional_pseudo_element<'t>(
+            &self,
+            name: CowRcStr<'i>,
+            parser: &mut CssParser<'i, 't>,
+        ) -> Result<PseudoElement, SelectorParseError<'i>> {
+            match_ignore_ascii_case! {&name,
+                "highlight" => return Ok(PseudoElement::Highlight(parser.expect_ident()?.as_ref().to_owned())),
+                _ => {}
+            }
+            Err(
+                parser.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(
+                    name,
+                )),
+            )
+        }
+
+        fn default_namespace(&self) -> Option<DummyAtom> {
+            self.default_ns.clone()
+        }
+
+        fn namespace_for_prefix(&self, prefix: &DummyAtom) -> Option<DummyAtom> {
+            self.ns_prefixes.get(prefix).cloned()
+        }
+    }
+
+    fn parse<'i>(
+        input: &'i str,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_relative(input, ParseRelative::No)
+    }
+
+    fn parse_relative<'i>(
+        input: &'i str,
+        parse_relative: ParseRelative,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_relative(input, &DummyParser::default(), parse_relative)
+    }
+
+    fn parse_expected<'i, 'a>(
+        input: &'i str,
+        expected: Option<&'a str>,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_expected(input, &DummyParser::default(), expected)
+    }
+
+    fn parse_relative_expected<'i, 'a>(
+        input: &'i str,
+        parse_relative: ParseRelative,
+        expected: Option<&'a str>,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_relative_expected(input, &DummyParser::default(), parse_relative, expected)
+    }
+
+    fn parse_ns<'i>(
+        input: &'i str,
+        parser: &DummyParser,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_relative(input, parser, ParseRelative::No)
+    }
+
+    fn parse_ns_relative<'i>(
+        input: &'i str,
+        parser: &DummyParser,
+        parse_relative: ParseRelative,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_relative_expected(input, parser, parse_relative, None)
+    }
+
+    fn parse_ns_expected<'i, 'a>(
+        input: &'i str,
+        parser: &DummyParser,
+        expected: Option<&'a str>,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        parse_ns_relative_expected(input, parser, ParseRelative::No, expected)
+    }
+
+    fn parse_ns_relative_expected<'i, 'a>(
+        input: &'i str,
+        parser: &DummyParser,
+        parse_relative: ParseRelative,
+        expected: Option<&'a str>,
+    ) -> Result<SelectorList<DummySelectorImpl>, SelectorParseError<'i>> {
+        let mut parser_input = ParserInput::new(input);
+        let result = SelectorList::parse(
+            parser,
+            &mut CssParser::new(&mut parser_input),
+            parse_relative,
+        );
+        if let Ok(ref selectors) = result {
+            // We can't assume that the serialized parsed selector will equal
+            // the input; for example, if there is no default namespace, '*|foo'
+            // should serialize to 'foo'.
+            assert_eq!(
+                selectors.to_css_string(),
+                match expected {
+                    Some(x) => x,
+                    None => input,
+                }
+            );
+        }
+        result
+    }
+
+    fn specificity(a: u32, b: u32, c: u32) -> u32 {
+        a << 20 | b << 10 | c
+    }
+
+    #[test]
+    fn test_empty() {
+        let mut input = ParserInput::new(":empty");
+        let list = SelectorList::parse(
+            &DummyParser::default(),
+            &mut CssParser::new(&mut input),
+            ParseRelative::No,
+        );
+        assert!(list.is_ok());
+    }
+
+    const MATHML: &str = "http://www.w3.org/1998/Math/MathML";
+    const SVG: &str = "http://www.w3.org/2000/svg";
+
+    #[test]
+    fn test_parsing() {
+        assert!(parse("").is_err());
+        assert!(parse(":lang(4)").is_err());
+        assert!(parse(":lang(en US)").is_err());
+        assert_eq!(
+            parse("EeÉ"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::LocalName(LocalName {
+                    name: DummyAtom::from("EeÉ"),
+                    lower_name: DummyAtom::from("eeÉ"),
+                })],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("|e"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ExplicitNoNamespace,
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("e"),
+                        lower_name: DummyAtom::from("e"),
+                    }),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // When the default namespace is not set, *| should be elided.
+        // https://github.com/servo/servo/pull/17537
+        assert_eq!(
+            parse_expected("*|e", Some("e")),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::LocalName(LocalName {
+                    name: DummyAtom::from("e"),
+                    lower_name: DummyAtom::from("e"),
+                })],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // When the default namespace is set, *| should _not_ be elided (as foo
+        // is no longer equivalent to *|foo--the former is only for foo in the
+        // default namespace).
+        // https://github.com/servo/servo/issues/16020
+        assert_eq!(
+            parse_ns(
+                "*|e",
+                &DummyParser::default_with_namespace(DummyAtom::from("https://mozilla.org"))
+            ),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ExplicitAnyNamespace,
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("e"),
+                        lower_name: DummyAtom::from("e"),
+                    }),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("*"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::ExplicitUniversalType],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("|*"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ExplicitNoNamespace,
+                    Component::ExplicitUniversalType,
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_expected("*|*", Some("*")),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::ExplicitUniversalType],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns(
+                "*|*",
+                &DummyParser::default_with_namespace(DummyAtom::from("https://mozilla.org"))
+            ),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ExplicitAnyNamespace,
+                    Component::ExplicitUniversalType,
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse(".foo:lang(en-US)"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Class(DummyAtom::from("foo")),
+                    Component::NonTSPseudoClass(PseudoClass::Lang("en-US".to_owned())),
+                ],
+                specificity(0, 2, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("#bar"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::ID(DummyAtom::from("bar"))],
+                specificity(1, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("e.foo#bar"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("e"),
+                        lower_name: DummyAtom::from("e"),
+                    }),
+                    Component::Class(DummyAtom::from("foo")),
+                    Component::ID(DummyAtom::from("bar")),
+                ],
+                specificity(1, 1, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("e.foo #bar"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("e"),
+                        lower_name: DummyAtom::from("e"),
+                    }),
+                    Component::Class(DummyAtom::from("foo")),
+                    Component::Combinator(Combinator::Descendant),
+                    Component::ID(DummyAtom::from("bar")),
+                ],
+                specificity(1, 1, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // Default namespace does not apply to attribute selectors
+        // https://github.com/mozilla/servo/pull/1652
+        let mut parser = DummyParser::default();
+        assert_eq!(
+            parse_ns("[Foo]", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::AttributeInNoNamespaceExists {
+                    local_name: DummyAtom::from("Foo"),
+                    local_name_lower: DummyAtom::from("foo"),
+                }],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert!(parse_ns("svg|circle", &parser).is_err());
+        parser
+            .ns_prefixes
+            .insert(DummyAtom("svg".into()), DummyAtom(SVG.into()));
+        assert_eq!(
+            parse_ns("svg|circle", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Namespace(DummyAtom("svg".into()), SVG.into()),
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("circle"),
+                        lower_name: DummyAtom::from("circle"),
+                    }),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns("svg|*", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Namespace(DummyAtom("svg".into()), SVG.into()),
+                    Component::ExplicitUniversalType,
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // Default namespace does not apply to attribute selectors
+        // https://github.com/mozilla/servo/pull/1652
+        // but it does apply to implicit type selectors
+        // https://github.com/servo/rust-selectors/pull/82
+        parser.default_ns = Some(MATHML.into());
+        assert_eq!(
+            parse_ns("[Foo]", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::AttributeInNoNamespaceExists {
+                        local_name: DummyAtom::from("Foo"),
+                        local_name_lower: DummyAtom::from("foo"),
+                    },
+                ],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // Default namespace does apply to type selectors
+        assert_eq!(
+            parse_ns("e", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("e"),
+                        lower_name: DummyAtom::from("e"),
+                    }),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns("*", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::ExplicitUniversalType,
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns("*|*", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ExplicitAnyNamespace,
+                    Component::ExplicitUniversalType,
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // Default namespace applies to universal and type selectors inside :not and :matches,
+        // but not otherwise.
+        assert_eq!(
+            parse_ns(":not(.cl)", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::Negation(SelectorList::from_vec(vec![Selector::from_vec(
+                        vec![Component::Class(DummyAtom::from("cl"))],
+                        specificity(0, 1, 0),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )])),
+                ],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns(":not(*)", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::Negation(SelectorList::from_vec(vec![Selector::from_vec(
+                        vec![
+                            Component::DefaultNamespace(MATHML.into()),
+                            Component::ExplicitUniversalType,
+                        ],
+                        specificity(0, 0, 0),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )]),),
+                ],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns(":not(e)", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::DefaultNamespace(MATHML.into()),
+                    Component::Negation(SelectorList::from_vec(vec![Selector::from_vec(
+                        vec![
+                            Component::DefaultNamespace(MATHML.into()),
+                            Component::LocalName(LocalName {
+                                name: DummyAtom::from("e"),
+                                lower_name: DummyAtom::from("e"),
+                            }),
+                        ],
+                        specificity(0, 0, 1),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )])),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse("[attr|=\"foo\"]"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::AttributeInNoNamespace {
+                    local_name: DummyAtom::from("attr"),
+                    operator: AttrSelectorOperator::DashMatch,
+                    value: DummyAttrValue::from("foo"),
+                    case_sensitivity: ParsedCaseSensitivity::CaseSensitive,
+                }],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // https://github.com/mozilla/servo/issues/1723
+        assert_eq!(
+            parse("::before"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Combinator(Combinator::PseudoElement),
+                    Component::PseudoElement(PseudoElement::Before),
+                ],
+                specificity(0, 0, 1),
+                SelectorFlags::HAS_PSEUDO,
+            )]))
+        );
+        assert_eq!(
+            parse("::before:hover"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Combinator(Combinator::PseudoElement),
+                    Component::PseudoElement(PseudoElement::Before),
+                    Component::NonTSPseudoClass(PseudoClass::Hover),
+                ],
+                specificity(0, 1, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT | SelectorFlags::HAS_PSEUDO,
+            )]))
+        );
+        assert_eq!(
+            parse("::before:hover:hover"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Combinator(Combinator::PseudoElement),
+                    Component::PseudoElement(PseudoElement::Before),
+                    Component::NonTSPseudoClass(PseudoClass::Hover),
+                    Component::NonTSPseudoClass(PseudoClass::Hover),
+                ],
+                specificity(0, 2, 1),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT | SelectorFlags::HAS_PSEUDO,
+            )]))
+        );
+        assert!(parse("::before:hover:lang(foo)").is_err());
+        assert!(parse("::before:hover .foo").is_err());
+        assert!(parse("::before .foo").is_err());
+        assert!(parse("::before ~ bar").is_err());
+        assert!(parse("::before:active").is_ok());
+
+        // https://github.com/servo/servo/issues/15335
+        assert!(parse(":: before").is_err());
+        assert_eq!(
+            parse("div ::after"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::LocalName(LocalName {
+                        name: DummyAtom::from("div"),
+                        lower_name: DummyAtom::from("div"),
+                    }),
+                    Component::Combinator(Combinator::Descendant),
+                    Component::Combinator(Combinator::PseudoElement),
+                    Component::PseudoElement(PseudoElement::After),
+                ],
+                specificity(0, 0, 2),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT | SelectorFlags::HAS_PSEUDO,
+            )]))
+        );
+        assert_eq!(
+            parse("#d1 > .ok"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ID(DummyAtom::from("d1")),
+                    Component::Combinator(Combinator::Child),
+                    Component::Class(DummyAtom::from("ok")),
+                ],
+                (1 << 20) + (1 << 10) + (0 << 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        parser.default_ns = None;
+        assert!(parse(":not(#provel.old)").is_ok());
+        assert!(parse(":not(#provel > old)").is_ok());
+        assert!(parse("table[rules]:not([rules=\"none\"]):not([rules=\"\"])").is_ok());
+        // https://github.com/servo/servo/issues/16017
+        assert_eq!(
+            parse_ns(":not(*)", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::Negation(SelectorList::from_vec(vec![
+                    Selector::from_vec(
+                        vec![Component::ExplicitUniversalType],
+                        specificity(0, 0, 0),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )
+                ]))],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        assert_eq!(
+            parse_ns(":not(|*)", &parser),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::Negation(SelectorList::from_vec(vec![
+                    Selector::from_vec(
+                        vec![
+                            Component::ExplicitNoNamespace,
+                            Component::ExplicitUniversalType,
+                        ],
+                        specificity(0, 0, 0),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )
+                ]))],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+        // *| should be elided if there is no default namespace.
+        // https://github.com/servo/servo/pull/17537
+        assert_eq!(
+            parse_ns_expected(":not(*|*)", &parser, Some(":not(*)")),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![Component::Negation(SelectorList::from_vec(vec![
+                    Selector::from_vec(
+                        vec![Component::ExplicitUniversalType],
+                        specificity(0, 0, 0),
+                        SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+                    )
+                ]))],
+                specificity(0, 0, 0),
+                SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )]))
+        );
+
+        assert!(parse("::highlight(foo)").is_ok());
+
+        assert!(parse("::slotted()").is_err());
+        assert!(parse("::slotted(div)").is_ok());
+        assert!(parse("::slotted(div).foo").is_err());
+        assert!(parse("::slotted(div + bar)").is_err());
+        assert!(parse("::slotted(div) + foo").is_err());
+
+        assert!(parse("::part()").is_err());
+        assert!(parse("::part(42)").is_err());
+        assert!(parse("::part(foo bar)").is_ok());
+        assert!(parse("::part(foo):hover").is_ok());
+        assert!(parse("::part(foo) + bar").is_err());
+
+        assert!(parse("div ::slotted(div)").is_ok());
+        assert!(parse("div + slot::slotted(div)").is_ok());
+        assert!(parse("div + slot::slotted(div.foo)").is_ok());
+        assert!(parse("slot::slotted(div,foo)::first-line").is_err());
+        assert!(parse("::slotted(div)::before").is_ok());
+        assert!(parse("slot::slotted(div,foo)").is_err());
+
+        assert!(parse("foo:where()").is_ok());
+        assert!(parse("foo:where(div, foo, .bar baz)").is_ok());
+        assert!(parse("foo:where(::before)").is_ok());
+    }
+
+    #[test]
+    fn parent_selector() {
+        assert!(parse("foo &").is_ok());
+        assert_eq!(
+            parse("#foo &.bar"),
+            Ok(SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ID(DummyAtom::from("foo")),
+                    Component::Combinator(Combinator::Descendant),
+                    Component::ParentSelector,
+                    Component::Class(DummyAtom::from("bar")),
+                ],
+                (1 << 20) + (1 << 10) + (0 << 0),
+                SelectorFlags::HAS_PARENT | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT
+            )]))
+        );
+
+        let parent = parse(".bar, div .baz").unwrap();
+        let child = parse("#foo &.bar").unwrap();
+        assert_eq!(
+            child.replace_parent_selector(&parent),
+            parse("#foo :is(.bar, div .baz).bar").unwrap()
+        );
+
+        let has_child = parse("#foo:has(&.bar)").unwrap();
+        assert_eq!(
+            has_child.replace_parent_selector(&parent),
+            parse("#foo:has(:is(.bar, div .baz).bar)").unwrap()
+        );
+
+        let child = parse_relative_expected("#foo", ParseRelative::ForNesting, Some("& #foo")).unwrap();
+        assert_eq!(
+            child.replace_parent_selector(&parent),
+            parse(":is(.bar, div .baz) #foo").unwrap()
+        );
+
+        let child =
+            parse_relative_expected("+ #foo", ParseRelative::ForNesting, Some("& + #foo")).unwrap();
+        assert_eq!(child, parse("& + #foo").unwrap());
+    }
+
+    #[test]
+    fn test_pseudo_iter() {
+        let list = parse("q::before").unwrap();
+        let selector = &list.slice()[0];
+        assert!(!selector.is_universal());
+        let mut iter = selector.iter();
+        assert_eq!(
+            iter.next(),
+            Some(&Component::PseudoElement(PseudoElement::Before))
+        );
+        assert_eq!(iter.next(), None);
+        let combinator = iter.next_sequence();
+        assert_eq!(combinator, Some(Combinator::PseudoElement));
+        assert!(matches!(iter.next(), Some(&Component::LocalName(..))));
+        assert_eq!(iter.next(), None);
+        assert_eq!(iter.next_sequence(), None);
+    }
+
+    #[test]
+    fn test_universal() {
+        let list = parse_ns(
+            "*|*::before",
+            &DummyParser::default_with_namespace(DummyAtom::from("https://mozilla.org")),
+        )
+        .unwrap();
+        let selector = &list.slice()[0];
+        assert!(selector.is_universal());
+    }
+
+    #[test]
+    fn test_empty_pseudo_iter() {
+        let list = parse("::before").unwrap();
+        let selector = &list.slice()[0];
+        assert!(selector.is_universal());
+        let mut iter = selector.iter();
+        assert_eq!(
+            iter.next(),
+            Some(&Component::PseudoElement(PseudoElement::Before))
+        );
+        assert_eq!(iter.next(), None);
+        assert_eq!(iter.next_sequence(), Some(Combinator::PseudoElement));
+        assert_eq!(iter.next(), None);
+        assert_eq!(iter.next_sequence(), None);
+    }
+
+    #[test]
+    fn test_parse_implicit_scope() {
+        assert_eq!(
+            parse_relative_expected(".foo", ParseRelative::ForScope, None).unwrap(),
+            SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ImplicitScope,
+                    Component::Combinator(Combinator::Descendant),
+                    Component::Class(DummyAtom::from("foo")),
+                ],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_SCOPE | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )])
+        );
+
+        assert_eq!(
+            parse_relative_expected(":scope .foo", ParseRelative::ForScope, None).unwrap(),
+            SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Scope,
+                    Component::Combinator(Combinator::Descendant),
+                    Component::Class(DummyAtom::from("foo")),
+                ],
+                specificity(0, 2, 0),
+                SelectorFlags::HAS_SCOPE | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )])
+        );
+
+        assert_eq!(
+            parse_relative_expected("> .foo", ParseRelative::ForScope, Some("> .foo")).unwrap(),
+            SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::ImplicitScope,
+                    Component::Combinator(Combinator::Child),
+                    Component::Class(DummyAtom::from("foo")),
+                ],
+                specificity(0, 1, 0),
+                SelectorFlags::HAS_SCOPE | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )])
+        );
+
+        assert_eq!(
+            parse_relative_expected(".foo :scope > .bar", ParseRelative::ForScope, None).unwrap(),
+            SelectorList::from_vec(vec![Selector::from_vec(
+                vec![
+                    Component::Class(DummyAtom::from("foo")),
+                    Component::Combinator(Combinator::Descendant),
+                    Component::Scope,
+                    Component::Combinator(Combinator::Child),
+                    Component::Class(DummyAtom::from("bar")),
+                ],
+                specificity(0, 3, 0),
+                SelectorFlags::HAS_SCOPE | SelectorFlags::HAS_NON_FEATURELESS_COMPONENT,
+            )])
+        );
+    }
+
+    #[test]
+    fn test_featureless() {
+        let featureless = parse(":host, :scope").unwrap();
+        assert_eq!(featureless.slice().len(), 2);
+        for selector in featureless.slice() {
+            assert!(!selector.flags().intersects(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT));
+        }
+
+        let non_featureless = parse(":host.foo, :scope.foo, :host .foo, :scope .foo").unwrap();
+        assert_eq!(non_featureless.slice().len(), 4);
+        for selector in non_featureless.slice() {
+            assert!(selector.flags().intersects(SelectorFlags::HAS_NON_FEATURELESS_COMPONENT));
+        }
+    }
+
+    struct TestVisitor {
+        seen: Vec<String>,
+    }
+
+    impl SelectorVisitor for TestVisitor {
+        type Impl = DummySelectorImpl;
+
+        fn visit_simple_selector(&mut self, s: &Component<DummySelectorImpl>) -> bool {
+            let mut dest = String::new();
+            s.to_css(&mut dest).unwrap();
+            self.seen.push(dest);
+            true
+        }
+    }
+
+    #[test]
+    fn visitor() {
+        let mut test_visitor = TestVisitor { seen: vec![] };
+        parse(":not(:hover) ~ label").unwrap().slice()[0].visit(&mut test_visitor);
+        assert!(test_visitor.seen.contains(&":hover".into()));
+
+        let mut test_visitor = TestVisitor { seen: vec![] };
+        parse("::before:hover").unwrap().slice()[0].visit(&mut test_visitor);
+        assert!(test_visitor.seen.contains(&":hover".into()));
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/cache.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/cache.rs
new file mode 100644
index 000000000000..d7681aa3a43a
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/cache.rs
@@ -0,0 +1,81 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use fxhash::FxHashMap;
+/// Relative selector cache. This is useful for following cases.
+/// First case is non-subject relative selector: Imagine `.anchor:has(<..>) ~ .foo`, with DOM
+/// `.anchor + .foo + .. + .foo`. Each match on `.foo` triggers `:has()` traversal that
+/// yields the same result. This is simple enough, since we just need to store
+/// the exact match on that anchor pass/fail.
+/// Second case is `querySelectorAll`: Imagine `querySelectorAll(':has(.a)')`, with DOM
+/// `div > .. > div > .a`. When the we perform the traversal at the top div,
+/// we basically end up evaluating `:has(.a)` for all anchors, which could be reused.
+/// Also consider the sibling version: `querySelectorAll(':has(~ .a)')` with DOM
+/// `div + .. + div + .a`.
+/// TODO(dshin): Second case is not yet handled. That is tracked in Bug 1845291.
+use std::hash::Hash;
+
+use crate::parser::{RelativeSelector, SelectorKey};
+use crate::{tree::OpaqueElement, SelectorImpl};
+
+/// Match data for a given element and a selector.
+#[derive(Clone, Copy)]
+pub enum RelativeSelectorCachedMatch {
+    /// This selector matches this element.
+    Matched,
+    /// This selector does not match this element.
+    NotMatched,
+}
+
+impl RelativeSelectorCachedMatch {
+    /// Is the cached result a match?
+    pub fn matched(&self) -> bool {
+        matches!(*self, Self::Matched)
+    }
+}
+
+#[derive(Clone, Copy, Hash, Eq, PartialEq)]
+struct Key {
+    element: OpaqueElement,
+    selector: SelectorKey,
+}
+
+impl Key {
+    pub fn new<Impl: SelectorImpl>(
+        element: OpaqueElement,
+        selector: &RelativeSelector<Impl>,
+    ) -> Self {
+        Key {
+            element,
+            selector: SelectorKey::new(&selector.selector),
+        }
+    }
+}
+
+/// Cache to speed up matching of relative selectors.
+#[derive(Default)]
+pub struct RelativeSelectorCache {
+    cache: FxHashMap<Key, RelativeSelectorCachedMatch>,
+}
+
+impl RelativeSelectorCache {
+    /// Add a relative selector match into the cache.
+    pub fn add<Impl: SelectorImpl>(
+        &mut self,
+        anchor: OpaqueElement,
+        selector: &RelativeSelector<Impl>,
+        matched: RelativeSelectorCachedMatch,
+    ) {
+        self.cache.insert(Key::new(anchor, selector), matched);
+    }
+
+    /// Check if we have a cache entry for the element.
+    pub fn lookup<Impl: SelectorImpl>(
+        &mut self,
+        element: OpaqueElement,
+        selector: &RelativeSelector<Impl>,
+    ) -> Option<RelativeSelectorCachedMatch> {
+        self.cache.get(&Key::new(element, selector)).copied()
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/filter.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/filter.rs
new file mode 100644
index 000000000000..3c3eb7d2fa56
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/filter.rs
@@ -0,0 +1,159 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+/// Bloom filter for relative selectors.
+use fxhash::FxHashMap;
+
+use crate::bloom::BloomFilter;
+use crate::context::QuirksMode;
+use crate::parser::{collect_selector_hashes, RelativeSelector, RelativeSelectorMatchHint};
+use crate::tree::{Element, OpaqueElement};
+use crate::SelectorImpl;
+
+enum Entry {
+    /// Filter lookup happened once. Construction of the filter is expensive,
+    /// so this is set when the element for subtree traversal is encountered.
+    Lookup,
+    /// Filter lookup happened more than once, and the filter for this element's
+    /// subtree traversal is constructed. Could use special handlings for pseudo-classes
+    /// such as `:hover` and `:focus`, see Bug 1845503.
+    HasFilter(Box<BloomFilter>),
+}
+
+#[derive(Clone, Copy, Hash, Eq, PartialEq)]
+enum TraversalKind {
+    Children,
+    Descendants,
+}
+
+fn add_to_filter<E: Element>(element: &E, filter: &mut BloomFilter, kind: TraversalKind) -> bool {
+    let mut child = element.first_element_child();
+    while let Some(e) = child {
+        if !e.add_element_unique_hashes(filter) {
+            return false;
+        }
+        if kind == TraversalKind::Descendants {
+            if !add_to_filter(&e, filter, kind) {
+                return false;
+            }
+        }
+        child = e.next_sibling_element();
+    }
+    true
+}
+
+#[derive(Clone, Copy, Hash, Eq, PartialEq)]
+struct Key(OpaqueElement, TraversalKind);
+
+/// Map of bloom filters for fast-rejecting relative selectors.
+#[derive(Default)]
+pub struct RelativeSelectorFilterMap {
+    map: FxHashMap<Key, Entry>,
+}
+
+fn fast_reject<Impl: SelectorImpl>(
+    selector: &RelativeSelector<Impl>,
+    quirks_mode: QuirksMode,
+    filter: &BloomFilter,
+) -> bool {
+    let mut hashes = [0u32; 4];
+    let mut len = 0;
+    // For inner selectors, we only collect from the single rightmost compound.
+    // This is because inner selectors can cause breakouts: e.g. `.anchor:has(:is(.a .b) .c)`
+    // can match when `.a` is the ancestor of `.anchor`. Including `.a` would possibly fast
+    // reject the subtree for not having `.a`, even if the selector would match.
+    // Technically, if the selector's traversal is non-sibling subtree, we can traverse
+    // inner selectors up to the point where a descendant/child combinator is encountered
+    // (e.g. In `.anchor:has(:is(.a ~ .b) .c)`, `.a` is guaranteed to be the a descendant
+    // of `.anchor`). While that can be separately handled, well, this is simpler.
+    collect_selector_hashes(
+        selector.selector.iter(),
+        quirks_mode,
+        &mut hashes,
+        &mut len,
+        |s| s.iter(),
+    );
+    for i in 0..len {
+        if !filter.might_contain_hash(hashes[i]) {
+            // Definitely rejected.
+            return true;
+        }
+    }
+    false
+}
+
+impl RelativeSelectorFilterMap {
+    fn get_filter<E: Element>(&mut self, element: &E, kind: TraversalKind) -> Option<&BloomFilter> {
+        // Insert flag to indicate that we looked up the filter once, and
+        // create the filter if and only if that flag is there.
+        let key = Key(element.opaque(), kind);
+        let entry = self
+            .map
+            .entry(key)
+            .and_modify(|entry| {
+                if !matches!(entry, Entry::Lookup) {
+                    return;
+                }
+                let mut filter = BloomFilter::new();
+                // Go through all children/descendants of this element and add their hashes.
+                if add_to_filter(element, &mut filter, kind) {
+                    *entry = Entry::HasFilter(Box::new(filter));
+                }
+            })
+            .or_insert(Entry::Lookup);
+        match entry {
+            Entry::Lookup => None,
+            Entry::HasFilter(ref filter) => Some(filter.as_ref()),
+        }
+    }
+
+    /// Potentially reject the given selector for this element.
+    /// This may seem redundant in presence of the cache, but the cache keys into the
+    /// selector-element pair specifically, while this filter keys to the element
+    /// and the traversal kind, so it is useful for handling multiple selectors
+    /// that effectively end up looking at the same(-ish, for siblings) subtree.
+    pub fn fast_reject<Impl: SelectorImpl, E: Element>(
+        &mut self,
+        element: &E,
+        selector: &RelativeSelector<Impl>,
+        quirks_mode: QuirksMode,
+    ) -> bool {
+        if matches!(
+            selector.match_hint,
+            RelativeSelectorMatchHint::InNextSibling
+        ) {
+            // Don't bother.
+            return false;
+        }
+        let is_sibling = matches!(
+            selector.match_hint,
+            RelativeSelectorMatchHint::InSibling |
+                RelativeSelectorMatchHint::InNextSiblingSubtree |
+                RelativeSelectorMatchHint::InSiblingSubtree
+        );
+        let is_subtree = matches!(
+            selector.match_hint,
+            RelativeSelectorMatchHint::InSubtree |
+                RelativeSelectorMatchHint::InNextSiblingSubtree |
+                RelativeSelectorMatchHint::InSiblingSubtree
+        );
+        let kind = if is_subtree {
+            TraversalKind::Descendants
+        } else {
+            TraversalKind::Children
+        };
+        if is_sibling {
+            // Contain the entirety of the parent's children/subtree in the filter, and use that.
+            // This is less likely to reject, especially for sibling subtree matches; however, it's less
+            // expensive memory-wise, compared to storing filters for each sibling.
+            element.parent_element().map_or(false, |parent| {
+                self.get_filter(&parent, kind)
+                    .map_or(false, |filter| fast_reject(selector, quirks_mode, filter))
+            })
+        } else {
+            self.get_filter(element, kind)
+                .map_or(false, |filter| fast_reject(selector, quirks_mode, filter))
+        }
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/mod.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/mod.rs
new file mode 100644
index 000000000000..6dd39f7327e6
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/mod.rs
@@ -0,0 +1,6 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+pub mod cache;
+pub mod filter;
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/sink.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/sink.rs
new file mode 100644
index 000000000000..dcdd7ff259dd
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/sink.rs
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Small helpers to abstract over different containers.
+#![deny(missing_docs)]
+
+use smallvec::{Array, SmallVec};
+
+/// A trait to abstract over a `push` method that may be implemented for
+/// different kind of types.
+///
+/// Used to abstract over `Array`, `SmallVec` and `Vec`, and also to implement a
+/// type which `push` method does only tweak a byte when we only need to check
+/// for the presence of something.
+pub trait Push<T> {
+    /// Push a value into self.
+    fn push(&mut self, value: T);
+}
+
+impl<T> Push<T> for Vec<T> {
+    fn push(&mut self, value: T) {
+        Vec::push(self, value);
+    }
+}
+
+impl<A: Array> Push<A::Item> for SmallVec<A> {
+    fn push(&mut self, value: A::Item) {
+        SmallVec::push(self, value);
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/tree.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/tree.rs
new file mode 100644
index 000000000000..c4765ebb78f7
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/tree.rs
@@ -0,0 +1,181 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Traits that nodes must implement. Breaks the otherwise-cyclic dependency
+//! between layout and style.
+
+use crate::attr::{AttrSelectorOperation, CaseSensitivity, NamespaceConstraint};
+use crate::bloom::BloomFilter;
+use crate::matching::{ElementSelectorFlags, MatchingContext};
+use crate::parser::SelectorImpl;
+use std::fmt::Debug;
+use std::ptr::NonNull;
+
+/// Opaque representation of an Element, for identity comparisons.
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct OpaqueElement(NonNull<()>);
+
+unsafe impl Send for OpaqueElement {}
+// This should be safe given that we do not provide a way to recover
+// the original (mutable) reference.
+unsafe impl Sync for OpaqueElement {}
+
+impl OpaqueElement {
+    /// Creates a new OpaqueElement from an arbitrarily-typed pointer.
+    pub fn new<T>(ptr: &T) -> Self {
+        unsafe {
+            OpaqueElement(NonNull::new_unchecked(
+                ptr as *const T as *const () as *mut (),
+            ))
+        }
+    }
+
+    /// Returns a const ptr to the contained reference.
+    pub unsafe fn as_const_ptr<T>(&self) -> *const T {
+        self.0.as_ptr() as *const T
+    }
+}
+
+pub trait Element: Sized + Clone + Debug {
+    type Impl: SelectorImpl;
+
+    /// Converts self into an opaque representation.
+    fn opaque(&self) -> OpaqueElement;
+
+    fn parent_element(&self) -> Option<Self>;
+
+    /// Whether the parent node of this element is a shadow root.
+    fn parent_node_is_shadow_root(&self) -> bool;
+
+    /// The host of the containing shadow root, if any.
+    fn containing_shadow_host(&self) -> Option<Self>;
+
+    /// The parent of a given pseudo-element, after matching a pseudo-element
+    /// selector.
+    ///
+    /// This is guaranteed to be called in a pseudo-element.
+    fn pseudo_element_originating_element(&self) -> Option<Self> {
+        debug_assert!(self.is_pseudo_element());
+        self.parent_element()
+    }
+
+    /// Whether we're matching on a pseudo-element.
+    fn is_pseudo_element(&self) -> bool;
+
+    /// Skips non-element nodes
+    fn prev_sibling_element(&self) -> Option<Self>;
+
+    /// Skips non-element nodes
+    fn next_sibling_element(&self) -> Option<Self>;
+
+    /// Skips non-element nodes
+    fn first_element_child(&self) -> Option<Self>;
+
+    fn is_html_element_in_html_document(&self) -> bool;
+
+    fn has_local_name(&self, local_name: &<Self::Impl as SelectorImpl>::BorrowedLocalName) -> bool;
+
+    /// Empty string for no namespace
+    fn has_namespace(&self, ns: &<Self::Impl as SelectorImpl>::BorrowedNamespaceUrl) -> bool;
+
+    /// Whether this element and the `other` element have the same local name and namespace.
+    fn is_same_type(&self, other: &Self) -> bool;
+
+    fn attr_matches(
+        &self,
+        ns: &NamespaceConstraint<&<Self::Impl as SelectorImpl>::NamespaceUrl>,
+        local_name: &<Self::Impl as SelectorImpl>::LocalName,
+        operation: &AttrSelectorOperation<&<Self::Impl as SelectorImpl>::AttrValue>,
+    ) -> bool;
+
+    fn has_attr_in_no_namespace(
+        &self,
+        local_name: &<Self::Impl as SelectorImpl>::LocalName,
+    ) -> bool {
+        self.attr_matches(
+            &NamespaceConstraint::Specific(&crate::parser::namespace_empty_string::<Self::Impl>()),
+            local_name,
+            &AttrSelectorOperation::Exists,
+        )
+    }
+
+    fn match_non_ts_pseudo_class(
+        &self,
+        pc: &<Self::Impl as SelectorImpl>::NonTSPseudoClass,
+        context: &mut MatchingContext<Self::Impl>,
+    ) -> bool;
+
+    fn match_pseudo_element(
+        &self,
+        pe: &<Self::Impl as SelectorImpl>::PseudoElement,
+        context: &mut MatchingContext<Self::Impl>,
+    ) -> bool;
+
+    /// Sets selector flags on the elemnt itself or the parent, depending on the
+    /// flags, which indicate what kind of work may need to be performed when
+    /// DOM state changes.
+    fn apply_selector_flags(&self, flags: ElementSelectorFlags);
+
+    /// Whether this element is a `link`.
+    fn is_link(&self) -> bool;
+
+    /// Returns whether the element is an HTML <slot> element.
+    fn is_html_slot_element(&self) -> bool;
+
+    /// Returns the assigned <slot> element this element is assigned to.
+    ///
+    /// Necessary for the `::slotted` pseudo-class.
+    fn assigned_slot(&self) -> Option<Self> {
+        None
+    }
+
+    fn has_id(
+        &self,
+        id: &<Self::Impl as SelectorImpl>::Identifier,
+        case_sensitivity: CaseSensitivity,
+    ) -> bool;
+
+    fn has_class(
+        &self,
+        name: &<Self::Impl as SelectorImpl>::Identifier,
+        case_sensitivity: CaseSensitivity,
+    ) -> bool;
+
+    fn has_custom_state(
+        &self,
+        name: &<Self::Impl as SelectorImpl>::Identifier,
+    ) -> bool;
+
+    /// Returns the mapping from the `exportparts` attribute in the reverse
+    /// direction, that is, in an outer-tree -> inner-tree direction.
+    fn imported_part(
+        &self,
+        name: &<Self::Impl as SelectorImpl>::Identifier,
+    ) -> Option<<Self::Impl as SelectorImpl>::Identifier>;
+
+    fn is_part(&self, name: &<Self::Impl as SelectorImpl>::Identifier) -> bool;
+
+    /// Returns whether this element matches `:empty`.
+    ///
+    /// That is, whether it does not contain any child element or any non-zero-length text node.
+    /// See http://dev.w3.org/csswg/selectors-3/#empty-pseudo
+    fn is_empty(&self) -> bool;
+
+    /// Returns whether this element matches `:root`,
+    /// i.e. whether it is the root element of a document.
+    ///
+    /// Note: this can be false even if `.parent_element()` is `None`
+    /// if the parent node is a `DocumentFragment`.
+    fn is_root(&self) -> bool;
+
+    /// Returns whether this element should ignore matching nth child
+    /// selector.
+    fn ignores_nth_child_selectors(&self) -> bool {
+        false
+    }
+
+    /// Add hashes unique to this element to the given filter, returning true
+    /// if any got added.
+    fn add_element_unique_hashes(&self, filter: &mut BloomFilter) -> bool;
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/visitor.rs b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/visitor.rs
new file mode 100644
index 000000000000..e4286c55532c
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/visitor.rs
@@ -0,0 +1,137 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Visitor traits for selectors.
+
+#![deny(missing_docs)]
+
+use crate::attr::NamespaceConstraint;
+use crate::parser::{Combinator, Component, RelativeSelector, Selector, SelectorImpl};
+use bitflags::bitflags;
+
+/// A trait to visit selector properties.
+///
+/// All the `visit_foo` methods return a boolean indicating whether the
+/// traversal should continue or not.
+pub trait SelectorVisitor: Sized {
+    /// The selector implementation this visitor wants to visit.
+    type Impl: SelectorImpl;
+
+    /// Visit an attribute selector that may match (there are other selectors
+    /// that may never match, like those containing whitespace or the empty
+    /// string).
+    fn visit_attribute_selector(
+        &mut self,
+        _namespace: &NamespaceConstraint<&<Self::Impl as SelectorImpl>::NamespaceUrl>,
+        _local_name: &<Self::Impl as SelectorImpl>::LocalName,
+        _local_name_lower: &<Self::Impl as SelectorImpl>::LocalName,
+    ) -> bool {
+        true
+    }
+
+    /// Visit a simple selector.
+    fn visit_simple_selector(&mut self, _: &Component<Self::Impl>) -> bool {
+        true
+    }
+
+    /// Visit a nested relative selector list. The caller is responsible to call visit
+    /// into the internal selectors if / as needed.
+    ///
+    /// The default implementation skips it altogether.
+    fn visit_relative_selector_list(&mut self, _list: &[RelativeSelector<Self::Impl>]) -> bool {
+        true
+    }
+
+    /// Visit a nested selector list. The caller is responsible to call visit
+    /// into the internal selectors if / as needed.
+    ///
+    /// The default implementation does this.
+    fn visit_selector_list(
+        &mut self,
+        _list_kind: SelectorListKind,
+        list: &[Selector<Self::Impl>],
+    ) -> bool {
+        for nested in list {
+            if !nested.visit(self) {
+                return false;
+            }
+        }
+        true
+    }
+
+    /// Visits a complex selector.
+    ///
+    /// Gets the combinator to the right of the selector, or `None` if the
+    /// selector is the rightmost one.
+    fn visit_complex_selector(&mut self, _combinator_to_right: Option<Combinator>) -> bool {
+        true
+    }
+}
+
+bitflags! {
+    /// The kinds of components the visitor is visiting the selector list of, if any
+    #[derive(Clone, Copy, Default)]
+    pub struct SelectorListKind: u8 {
+        /// The visitor is inside :not(..)
+        const NEGATION = 1 << 0;
+        /// The visitor is inside :is(..)
+        const IS = 1 << 1;
+        /// The visitor is inside :where(..)
+        const WHERE = 1 << 2;
+        /// The visitor is inside :nth-child(.. of <selector list>) or
+        /// :nth-last-child(.. of <selector list>)
+        const NTH_OF = 1 << 3;
+        /// The visitor is inside :has(..)
+        const HAS = 1 << 4;
+    }
+}
+
+impl SelectorListKind {
+    /// Construct a SelectorListKind for the corresponding component.
+    pub fn from_component<Impl: SelectorImpl>(component: &Component<Impl>) -> Self {
+        match component {
+            Component::Negation(_) => SelectorListKind::NEGATION,
+            Component::Is(_) => SelectorListKind::IS,
+            Component::Where(_) => SelectorListKind::WHERE,
+            Component::NthOf(_) => SelectorListKind::NTH_OF,
+            _ => SelectorListKind::empty(),
+        }
+    }
+
+    /// Whether the visitor is inside :not(..)
+    pub fn in_negation(&self) -> bool {
+        self.intersects(SelectorListKind::NEGATION)
+    }
+
+    /// Whether the visitor is inside :is(..)
+    pub fn in_is(&self) -> bool {
+        self.intersects(SelectorListKind::IS)
+    }
+
+    /// Whether the visitor is inside :where(..)
+    pub fn in_where(&self) -> bool {
+        self.intersects(SelectorListKind::WHERE)
+    }
+
+    /// Whether the visitor is inside :nth-child(.. of <selector list>) or
+    /// :nth-last-child(.. of <selector list>)
+    pub fn in_nth_of(&self) -> bool {
+        self.intersects(SelectorListKind::NTH_OF)
+    }
+
+    /// Whether the visitor is inside :has(..)
+    pub fn in_has(&self) -> bool {
+        self.intersects(SelectorListKind::HAS)
+    }
+
+    /// Whether this nested selector is relevant for nth-of dependencies.
+    pub fn relevant_to_nth_of_dependencies(&self) -> bool {
+        // Order of nesting for `:has` and `:nth-child(.. of ..)` doesn't matter, because:
+        // * `:has(:nth-child(.. of ..))`: The location of the anchoring element is
+        //   independent from where `:nth-child(.. of ..)` is applied.
+        // * `:nth-child(.. of :has(..))`: Invalidations inside `:has` must first use the
+        //   `:has` machinary to find the anchor, then carry out the remaining invalidation.
+        self.in_nth_of() && !self.in_has()
+    }
+}
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo-checksum.json b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo-checksum.json
new file mode 100644
index 000000000000..697c9ce2fbb4
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{}}
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo_vcs_info.json b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo_vcs_info.json
new file mode 100644
index 000000000000..0c2743c768bd
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "eb13715da7ad499b54637d037aaa8ce7578dfdfc"
+  },
+  "path_in_vcs": "servo/components/servo_arc"
+}
\ No newline at end of file
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml
new file mode 100644
index 000000000000..59e16c65f5e1
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml
@@ -0,0 +1,44 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "servo_arc"
+version = "0.4.0"
+authors = ["The Servo Project Developers"]
+build = false
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "A fork of std::sync::Arc with some extra functionality and without weak references"
+readme = false
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/servo/stylo"
+
+[lib]
+name = "servo_arc"
+path = "lib.rs"
+
+[dependencies.serde]
+version = "1.0"
+optional = true
+
+[dependencies.stable_deref_trait]
+version = "1.0.0"
+
+[features]
+gecko_refcount_logging = []
+servo = [
+    "serde",
+    "track_alloc_size",
+]
+track_alloc_size = []
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml.orig b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml.orig
new file mode 100644
index 000000000000..8b0976b75d9f
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/Cargo.toml.orig
@@ -0,0 +1,21 @@
+[package]
+name = "servo_arc"
+version = "0.4.0"
+authors = ["The Servo Project Developers"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/servo/stylo"
+description = "A fork of std::sync::Arc with some extra functionality and without weak references"
+edition = "2021"
+
+[lib]
+name = "servo_arc"
+path = "lib.rs"
+
+[features]
+gecko_refcount_logging = []
+servo = ["serde", "track_alloc_size"]
+track_alloc_size = []
+
+[dependencies]
+serde = { version = "1.0", optional = true }
+stable_deref_trait = "1.0.0"
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-APACHE b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-APACHE
new file mode 100644
index 000000000000..16fe87b06e80
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
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+   "License" shall mean the terms and conditions for use, reproduction,
+   and distribution as defined by Sections 1 through 9 of this document.
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+   You may add Your own copyright statement to Your modifications and
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+   the conditions stated in this License.
+
+5. Submission of Contributions. Unless You explicitly state otherwise,
+   any Contribution intentionally submitted for inclusion in the Work
+   by You to the Licensor shall be under the terms and conditions of
+   this License, without any additional terms or conditions.
+   Notwithstanding the above, nothing herein shall supersede or modify
+   the terms of any separate license agreement you may have executed
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+6. Trademarks. This License does not grant permission to use the trade
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+
+7. Disclaimer of Warranty. Unless required by applicable law or
+   agreed to in writing, Licensor provides the Work (and each
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+8. Limitation of Liability. In no event and under no legal theory,
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+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
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+You may obtain a copy of the License at
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+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
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+See the License for the specific language governing permissions and
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diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-MIT b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-MIT
new file mode 100644
index 000000000000..31aa79387f27
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/LICENSE-MIT
@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs
new file mode 100644
index 000000000000..77eb5ac89a88
--- /dev/null
+++ b/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs
@@ -0,0 +1,1198 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Fork of Arc for Servo. This has the following advantages over std::sync::Arc:
+//!
+//! * We don't waste storage on the weak reference count.
+//! * We don't do extra RMU operations to handle the possibility of weak references.
+//! * We can experiment with arena allocation (todo).
+//! * We can add methods to support our custom use cases [1].
+//! * We have support for dynamically-sized types (see from_header_and_iter).
+//! * We have support for thin arcs to unsized types (see ThinArc).
+//! * We have support for references to static data, which don't do any
+//!   refcounting.
+//!
+//! [1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1360883
+
+// The semantics of `Arc` are already documented in the Rust docs, so we don't
+// duplicate those here.
+#![allow(missing_docs)]
+
+#[cfg(feature = "servo")]
+use serde::{Deserialize, Serialize};
+use stable_deref_trait::{CloneStableDeref, StableDeref};
+use std::alloc::{self, Layout};
+use std::borrow;
+use std::cmp::Ordering;
+use std::fmt;
+use std::hash::{Hash, Hasher};
+use std::marker::PhantomData;
+use std::mem::{self, align_of, size_of};
+use std::ops::{Deref, DerefMut};
+use std::os::raw::c_void;
+use std::process;
+use std::ptr;
+use std::sync::atomic;
+use std::sync::atomic::Ordering::{Acquire, Relaxed, Release};
+use std::{isize, usize};
+
+/// A soft limit on the amount of references that may be made to an `Arc`.
+///
+/// Going above this limit will abort your program (although not
+/// necessarily) at _exactly_ `MAX_REFCOUNT + 1` references.
+const MAX_REFCOUNT: usize = (isize::MAX) as usize;
+
+/// Special refcount value that means the data is not reference counted,
+/// and that the `Arc` is really acting as a read-only static reference.
+const STATIC_REFCOUNT: usize = usize::MAX;
+
+/// An atomically reference counted shared pointer
+///
+/// See the documentation for [`Arc`] in the standard library. Unlike the
+/// standard library `Arc`, this `Arc` does not support weak reference counting.
+///
+/// See the discussion in https://github.com/rust-lang/rust/pull/60594 for the
+/// usage of PhantomData.
+///
+/// [`Arc`]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html
+///
+/// cbindgen:derive-eq=false
+/// cbindgen:derive-neq=false
+#[repr(C)]
+pub struct Arc<T: ?Sized> {
+    p: ptr::NonNull<ArcInner<T>>,
+    phantom: PhantomData<T>,
+}
+
+/// An `Arc` that is known to be uniquely owned
+///
+/// When `Arc`s are constructed, they are known to be
+/// uniquely owned. In such a case it is safe to mutate
+/// the contents of the `Arc`. Normally, one would just handle
+/// this by mutating the data on the stack before allocating the
+/// `Arc`, however it's possible the data is large or unsized
+/// and you need to heap-allocate it earlier in such a way
+/// that it can be freely converted into a regular `Arc` once you're
+/// done.
+///
+/// `UniqueArc` exists for this purpose, when constructed it performs
+/// the same allocations necessary for an `Arc`, however it allows mutable access.
+/// Once the mutation is finished, you can call `.shareable()` and get a regular `Arc`
+/// out of it.
+///
+/// Ignore the doctest below there's no way to skip building with refcount
+/// logging during doc tests (see rust-lang/rust#45599).
+///
+/// ```rust,ignore
+/// # use servo_arc::UniqueArc;
+/// let data = [1, 2, 3, 4, 5];
+/// let mut x = UniqueArc::new(data);
+/// x[4] = 7; // mutate!
+/// let y = x.shareable(); // y is an Arc<T>
+/// ```
+pub struct UniqueArc<T: ?Sized>(Arc<T>);
+
+impl<T> UniqueArc<T> {
+    #[inline]
+    /// Construct a new UniqueArc
+    pub fn new(data: T) -> Self {
+        UniqueArc(Arc::new(data))
+    }
+
+    /// Construct an uninitialized arc
+    #[inline]
+    pub fn new_uninit() -> UniqueArc<mem::MaybeUninit<T>> {
+        unsafe {
+            let layout = Layout::new::<ArcInner<mem::MaybeUninit<T>>>();
+            let ptr = alloc::alloc(layout);
+            let mut p = ptr::NonNull::new(ptr)
+                .unwrap_or_else(|| alloc::handle_alloc_error(layout))
+                .cast::<ArcInner<mem::MaybeUninit<T>>>();
+            ptr::write(&mut p.as_mut().count, atomic::AtomicUsize::new(1));
+            #[cfg(feature = "track_alloc_size")]
+            ptr::write(&mut p.as_mut().alloc_size, layout.size());
+
+            #[cfg(feature = "gecko_refcount_logging")]
+            {
+                NS_LogCtor(p.as_ptr() as *mut _, b"ServoArc\0".as_ptr() as *const _, 8)
+            }
+
+            UniqueArc(Arc {
+                p,
+                phantom: PhantomData,
+            })
+        }
+    }
+
+    #[inline]
+    /// Convert to a shareable Arc<T> once we're done mutating it
+    pub fn shareable(self) -> Arc<T> {
+        self.0
+    }
+}
+
+impl<T> UniqueArc<mem::MaybeUninit<T>> {
+    /// Convert to an initialized Arc.
+    #[inline]
+    pub unsafe fn assume_init(this: Self) -> UniqueArc<T> {
+        UniqueArc(Arc {
+            p: mem::ManuallyDrop::new(this).0.p.cast(),
+            phantom: PhantomData,
+        })
+    }
+}
+
+impl<T> Deref for UniqueArc<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        &*self.0
+    }
+}
+
+impl<T> DerefMut for UniqueArc<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        // We know this to be uniquely owned
+        unsafe { &mut (*self.0.ptr()).data }
+    }
+}
+
+unsafe impl<T: ?Sized + Sync + Send> Send for Arc<T> {}
+unsafe impl<T: ?Sized + Sync + Send> Sync for Arc<T> {}
+
+/// The object allocated by an Arc<T>
+///
+/// See https://github.com/mozilla/cbindgen/issues/937 for the derive-{eq,neq}=false. But we don't
+/// use those anyways so we can just disable them.
+/// cbindgen:derive-eq=false
+/// cbindgen:derive-neq=false
+#[repr(C)]
+struct ArcInner<T: ?Sized> {
+    count: atomic::AtomicUsize,
+    // NOTE(emilio): This needs to be here so that HeaderSlice<> is deallocated properly if the
+    // allocator relies on getting the right Layout. We don't need to track the right alignment,
+    // since we know that statically.
+    //
+    // This member could be completely avoided once min_specialization feature is stable (by
+    // implementing a trait for HeaderSlice that gives you the right layout). For now, servo-only
+    // since Gecko doesn't need it (its allocator doesn't need the size for the alignments we care
+    // about). See https://github.com/rust-lang/rust/issues/31844.
+    #[cfg(feature = "track_alloc_size")]
+    alloc_size: usize,
+    data: T,
+}
+
+unsafe impl<T: ?Sized + Sync + Send> Send for ArcInner<T> {}
+unsafe impl<T: ?Sized + Sync + Send> Sync for ArcInner<T> {}
+
+/// Computes the offset of the data field within ArcInner.
+fn data_offset<T>() -> usize {
+    let size = size_of::<ArcInner<()>>();
+    let align = align_of::<T>();
+    // https://github.com/rust-lang/rust/blob/1.36.0/src/libcore/alloc.rs#L187-L207
+    size.wrapping_add(align).wrapping_sub(1) & !align.wrapping_sub(1)
+}
+
+impl<T> Arc<T> {
+    /// Construct an `Arc<T>`
+    #[inline]
+    pub fn new(data: T) -> Self {
+        let layout = Layout::new::<ArcInner<T>>();
+        let p = unsafe {
+            let ptr = ptr::NonNull::new(alloc::alloc(layout))
+                .unwrap_or_else(|| alloc::handle_alloc_error(layout))
+                .cast::<ArcInner<T>>();
+            ptr::write(ptr.as_ptr(), ArcInner {
+                count: atomic::AtomicUsize::new(1),
+                #[cfg(feature = "track_alloc_size")]
+                alloc_size: layout.size(),
+                data,
+            });
+            ptr
+        };
+
+        #[cfg(feature = "gecko_refcount_logging")]
+        unsafe {
+            // FIXME(emilio): Would be so amazing to have
+            // std::intrinsics::type_name() around, so that we could also report
+            // a real size.
+            NS_LogCtor(p.as_ptr() as *mut _, b"ServoArc\0".as_ptr() as *const _, 8);
+        }
+
+        Arc {
+            p,
+            phantom: PhantomData,
+        }
+    }
+
+    /// Construct an intentionally-leaked arc.
+    #[inline]
+    pub fn new_leaked(data: T) -> Self {
+        let arc = Self::new(data);
+        arc.mark_as_intentionally_leaked();
+        arc
+    }
+
+    /// Convert the Arc<T> to a raw pointer, suitable for use across FFI
+    ///
+    /// Note: This returns a pointer to the data T, which is offset in the allocation.
+    #[inline]
+    pub fn into_raw(this: Self) -> *const T {
+        let ptr = unsafe { &((*this.ptr()).data) as *const _ };
+        mem::forget(this);
+        ptr
+    }
+
+    /// Reconstruct the Arc<T> from a raw pointer obtained from into_raw()
+    ///
+    /// Note: This raw pointer will be offset in the allocation and must be preceded
+    /// by the atomic count.
+    #[inline]
+    pub unsafe fn from_raw(ptr: *const T) -> Self {
+        // To find the corresponding pointer to the `ArcInner` we need
+        // to subtract the offset of the `data` field from the pointer.
+        let ptr = (ptr as *const u8).sub(data_offset::<T>());
+        Arc {
+            p: ptr::NonNull::new_unchecked(ptr as *mut ArcInner<T>),
+            phantom: PhantomData,
+        }
+    }
+
+    /// Like from_raw, but returns an addrefed arc instead.
+    #[inline]
+    pub unsafe fn from_raw_addrefed(ptr: *const T) -> Self {
+        let arc = Self::from_raw(ptr);
+        mem::forget(arc.clone());
+        arc
+    }
+
+    /// Create a new static Arc<T> (one that won't reference count the object)
+    /// and place it in the allocation provided by the specified `alloc`
+    /// function.
+    ///
+    /// `alloc` must return a pointer into a static allocation suitable for
+    /// storing data with the `Layout` passed into it. The pointer returned by
+    /// `alloc` will not be freed.
+    #[inline]
+    pub unsafe fn new_static<F>(alloc: F, data: T) -> Arc<T>
+    where
+        F: FnOnce(Layout) -> *mut u8,
+    {
+        let layout = Layout::new::<ArcInner<T>>();
+        let ptr = alloc(layout) as *mut ArcInner<T>;
+
+        let x = ArcInner {
+            count: atomic::AtomicUsize::new(STATIC_REFCOUNT),
+            #[cfg(feature = "track_alloc_size")]
+            alloc_size: layout.size(),
+            data,
+        };
+
+        ptr::write(ptr, x);
+
+        Arc {
+            p: ptr::NonNull::new_unchecked(ptr),
+            phantom: PhantomData,
+        }
+    }
+
+    /// Produce a pointer to the data that can be converted back
+    /// to an Arc. This is basically an `&Arc<T>`, without the extra indirection.
+    /// It has the benefits of an `&T` but also knows about the underlying refcount
+    /// and can be converted into more `Arc<T>`s if necessary.
+    #[inline]
+    pub fn borrow_arc<'a>(&'a self) -> ArcBorrow<'a, T> {
+        ArcBorrow(&**self)
+    }
+
+    /// Returns the address on the heap of the Arc itself -- not the T within it -- for memory
+    /// reporting.
+    ///
+    /// If this is a static reference, this returns null.
+    pub fn heap_ptr(&self) -> *const c_void {
+        if self.inner().count.load(Relaxed) == STATIC_REFCOUNT {
+            ptr::null()
+        } else {
+            self.p.as_ptr() as *const ArcInner<T> as *const c_void
+        }
+    }
+}
+
+impl<T: ?Sized> Arc<T> {
+    #[inline]
+    fn inner(&self) -> &ArcInner<T> {
+        // This unsafety is ok because while this arc is alive we're guaranteed
+        // that the inner pointer is valid. Furthermore, we know that the
+        // `ArcInner` structure itself is `Sync` because the inner data is
+        // `Sync` as well, so we're ok loaning out an immutable pointer to these
+        // contents.
+        unsafe { &*self.ptr() }
+    }
+
+    #[inline(always)]
+    fn record_drop(&self) {
+        #[cfg(feature = "gecko_refcount_logging")]
+        unsafe {
+            NS_LogDtor(self.ptr() as *mut _, b"ServoArc\0".as_ptr() as *const _, 8);
+        }
+    }
+
+    /// Marks this `Arc` as intentionally leaked for the purposes of refcount
+    /// logging.
+    ///
+    /// It's a logic error to call this more than once, but it's not unsafe, as
+    /// it'd just report negative leaks.
+    #[inline(always)]
+    pub fn mark_as_intentionally_leaked(&self) {
+        self.record_drop();
+    }
+
+    // Non-inlined part of `drop`. Just invokes the destructor and calls the
+    // refcount logging machinery if enabled.
+    #[inline(never)]
+    unsafe fn drop_slow(&mut self) {
+        self.record_drop();
+        let inner = self.ptr();
+
+        let layout = Layout::for_value(&*inner);
+        #[cfg(feature = "track_alloc_size")]
+        let layout = Layout::from_size_align_unchecked((*inner).alloc_size, layout.align());
+
+        std::ptr::drop_in_place(inner);
+        alloc::dealloc(inner as *mut _, layout);
+    }
+
+    /// Test pointer equality between the two Arcs, i.e. they must be the _same_
+    /// allocation
+    #[inline]
+    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+        this.raw_ptr() == other.raw_ptr()
+    }
+
+    fn ptr(&self) -> *mut ArcInner<T> {
+        self.p.as_ptr()
+    }
+
+    /// Returns a raw ptr to the underlying allocation.
+    pub fn raw_ptr(&self) -> ptr::NonNull<()> {
+        self.p.cast()
+    }
+}
+
+#[cfg(feature = "gecko_refcount_logging")]
+extern "C" {
+    fn NS_LogCtor(
+        aPtr: *mut std::os::raw::c_void,
+        aTypeName: *const std::os::raw::c_char,
+        aSize: u32,
+    );
+    fn NS_LogDtor(
+        aPtr: *mut std::os::raw::c_void,
+        aTypeName: *const std::os::raw::c_char,
+        aSize: u32,
+    );
+}
+
+impl<T: ?Sized> Clone for Arc<T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        // NOTE(emilio): If you change anything here, make sure that the
+        // implementation in layout/style/ServoStyleConstsInlines.h matches!
+        //
+        // Using a relaxed ordering to check for STATIC_REFCOUNT is safe, since
+        // `count` never changes between STATIC_REFCOUNT and other values.
+        if self.inner().count.load(Relaxed) != STATIC_REFCOUNT {
+            // Using a relaxed ordering is alright here, as knowledge of the
+            // original reference prevents other threads from erroneously deleting
+            // the object.
+            //
+            // As explained in the [Boost documentation][1], Increasing the
+            // reference counter can always be done with memory_order_relaxed: New
+            // references to an object can only be formed from an existing
+            // reference, and passing an existing reference from one thread to
+            // another must already provide any required synchronization.
+            //
+            // [1]: (www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html)
+            let old_size = self.inner().count.fetch_add(1, Relaxed);
+
+            // However we need to guard against massive refcounts in case someone
+            // is `mem::forget`ing Arcs. If we don't do this the count can overflow
+            // and users will use-after free. We racily saturate to `isize::MAX` on
+            // the assumption that there aren't ~2 billion threads incrementing
+            // the reference count at once. This branch will never be taken in
+            // any realistic program.
+            //
+            // We abort because such a program is incredibly degenerate, and we
+            // don't care to support it.
+            if old_size > MAX_REFCOUNT {
+                process::abort();
+            }
+        }
+
+        unsafe {
+            Arc {
+                p: ptr::NonNull::new_unchecked(self.ptr()),
+                phantom: PhantomData,
+            }
+        }
+    }
+}
+
+impl<T: ?Sized> Deref for Arc<T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &T {
+        &self.inner().data
+    }
+}
+
+impl<T: Clone> Arc<T> {
+    /// Makes a mutable reference to the `Arc`, cloning if necessary
+    ///
+    /// This is functionally equivalent to [`Arc::make_mut`][mm] from the standard library.
+    ///
+    /// If this `Arc` is uniquely owned, `make_mut()` will provide a mutable
+    /// reference to the contents. If not, `make_mut()` will create a _new_ `Arc`
+    /// with a copy of the contents, update `this` to point to it, and provide
+    /// a mutable reference to its contents.
+    ///
+    /// This is useful for implementing copy-on-write schemes where you wish to
+    /// avoid copying things if your `Arc` is not shared.
+    ///
+    /// [mm]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.make_mut
+    #[inline]
+    pub fn make_mut(this: &mut Self) -> &mut T {
+        if !this.is_unique() {
+            // Another pointer exists; clone
+            *this = Arc::new((**this).clone());
+        }
+
+        unsafe {
+            // This unsafety is ok because we're guaranteed that the pointer
+            // returned is the *only* pointer that will ever be returned to T. Our
+            // reference count is guaranteed to be 1 at this point, and we required
+            // the Arc itself to be `mut`, so we're returning the only possible
+            // reference to the inner data.
+            &mut (*this.ptr()).data
+        }
+    }
+}
+
+impl<T: ?Sized> Arc<T> {
+    /// Provides mutable access to the contents _if_ the `Arc` is uniquely owned.
+    #[inline]
+    pub fn get_mut(this: &mut Self) -> Option<&mut T> {
+        if this.is_unique() {
+            unsafe {
+                // See make_mut() for documentation of the threadsafety here.
+                Some(&mut (*this.ptr()).data)
+            }
+        } else {
+            None
+        }
+    }
+
+    /// Whether or not the `Arc` is a static reference.
+    #[inline]
+    pub fn is_static(&self) -> bool {
+        // Using a relaxed ordering to check for STATIC_REFCOUNT is safe, since
+        // `count` never changes between STATIC_REFCOUNT and other values.
+        self.inner().count.load(Relaxed) == STATIC_REFCOUNT
+    }
+
+    /// Whether or not the `Arc` is uniquely owned (is the refcount 1?) and not
+    /// a static reference.
+    #[inline]
+    pub fn is_unique(&self) -> bool {
+        // See the extensive discussion in [1] for why this needs to be Acquire.
+        //
+        // [1] https://github.com/servo/servo/issues/21186
+        self.inner().count.load(Acquire) == 1
+    }
+}
+
+impl<T: ?Sized> Drop for Arc<T> {
+    #[inline]
+    fn drop(&mut self) {
+        // NOTE(emilio): If you change anything here, make sure that the
+        // implementation in layout/style/ServoStyleConstsInlines.h matches!
+        if self.is_static() {
+            return;
+        }
+
+        // Because `fetch_sub` is already atomic, we do not need to synchronize
+        // with other threads unless we are going to delete the object.
+        if self.inner().count.fetch_sub(1, Release) != 1 {
+            return;
+        }
+
+        // FIXME(bholley): Use the updated comment when [2] is merged.
+        //
+        // This load is needed to prevent reordering of use of the data and
+        // deletion of the data.  Because it is marked `Release`, the decreasing
+        // of the reference count synchronizes with this `Acquire` load. This
+        // means that use of the data happens before decreasing the reference
+        // count, which happens before this load, which happens before the
+        // deletion of the data.
+        //
+        // As explained in the [Boost documentation][1],
+        //
+        // > It is important to enforce any possible access to the object in one
+        // > thread (through an existing reference) to *happen before* deleting
+        // > the object in a different thread. This is achieved by a "release"
+        // > operation after dropping a reference (any access to the object
+        // > through this reference must obviously happened before), and an
+        // > "acquire" operation before deleting the object.
+        //
+        // [1]: (www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html)
+        // [2]: https://github.com/rust-lang/rust/pull/41714
+        self.inner().count.load(Acquire);
+
+        unsafe {
+            self.drop_slow();
+        }
+    }
+}
+
+impl<T: ?Sized + PartialEq> PartialEq for Arc<T> {
+    fn eq(&self, other: &Arc<T>) -> bool {
+        Self::ptr_eq(self, other) || *(*self) == *(*other)
+    }
+
+    fn ne(&self, other: &Arc<T>) -> bool {
+        !Self::ptr_eq(self, other) && *(*self) != *(*other)
+    }
+}
+
+impl<T: ?Sized + PartialOrd> PartialOrd for Arc<T> {
+    fn partial_cmp(&self, other: &Arc<T>) -> Option<Ordering> {
+        (**self).partial_cmp(&**other)
+    }
+
+    fn lt(&self, other: &Arc<T>) -> bool {
+        *(*self) < *(*other)
+    }
+
+    fn le(&self, other: &Arc<T>) -> bool {
+        *(*self) <= *(*other)
+    }
+
+    fn gt(&self, other: &Arc<T>) -> bool {
+        *(*self) > *(*other)
+    }
+
+    fn ge(&self, other: &Arc<T>) -> bool {
+        *(*self) >= *(*other)
+    }
+}
+impl<T: ?Sized + Ord> Ord for Arc<T> {
+    fn cmp(&self, other: &Arc<T>) -> Ordering {
+        (**self).cmp(&**other)
+    }
+}
+impl<T: ?Sized + Eq> Eq for Arc<T> {}
+
+impl<T: ?Sized + fmt::Display> fmt::Display for Arc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&**self, f)
+    }
+}
+
+impl<T: ?Sized + fmt::Debug> fmt::Debug for Arc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&**self, f)
+    }
+}
+
+impl<T: ?Sized> fmt::Pointer for Arc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&self.ptr(), f)
+    }
+}
+
+impl<T: Default> Default for Arc<T> {
+    fn default() -> Arc<T> {
+        Arc::new(Default::default())
+    }
+}
+
+impl<T: ?Sized + Hash> Hash for Arc<T> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        (**self).hash(state)
+    }
+}
+
+impl<T> From<T> for Arc<T> {
+    #[inline]
+    fn from(t: T) -> Self {
+        Arc::new(t)
+    }
+}
+
+impl<T: ?Sized> borrow::Borrow<T> for Arc<T> {
+    #[inline]
+    fn borrow(&self) -> &T {
+        &**self
+    }
+}
+
+impl<T: ?Sized> AsRef<T> for Arc<T> {
+    #[inline]
+    fn as_ref(&self) -> &T {
+        &**self
+    }
+}
+
+unsafe impl<T: ?Sized> StableDeref for Arc<T> {}
+unsafe impl<T: ?Sized> CloneStableDeref for Arc<T> {}
+
+#[cfg(feature = "servo")]
+impl<'de, T: Deserialize<'de>> Deserialize<'de> for Arc<T> {
+    fn deserialize<D>(deserializer: D) -> Result<Arc<T>, D::Error>
+    where
+        D: ::serde::de::Deserializer<'de>,
+    {
+        T::deserialize(deserializer).map(Arc::new)
+    }
+}
+
+#[cfg(feature = "servo")]
+impl<T: Serialize> Serialize for Arc<T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: ::serde::ser::Serializer,
+    {
+        (**self).serialize(serializer)
+    }
+}
+
+/// Structure to allow Arc-managing some fixed-sized data and a variably-sized
+/// slice in a single allocation.
+///
+/// cbindgen:derive-eq=false
+/// cbindgen:derive-neq=false
+#[derive(Eq)]
+#[repr(C)]
+pub struct HeaderSlice<H, T> {
+    /// The fixed-sized data.
+    pub header: H,
+
+    /// The length of the slice at our end.
+    len: usize,
+
+    /// The dynamically-sized data.
+    data: [T; 0],
+}
+
+impl<H: PartialEq, T: PartialEq> PartialEq for HeaderSlice<H, T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.header == other.header && self.slice() == other.slice()
+    }
+}
+
+impl<H, T> Drop for HeaderSlice<H, T> {
+    fn drop(&mut self) {
+        unsafe {
+            let mut ptr = self.data_mut();
+            for _ in 0..self.len {
+                std::ptr::drop_in_place(ptr);
+                ptr = ptr.offset(1);
+            }
+        }
+    }
+}
+
+impl<H: fmt::Debug, T: fmt::Debug> fmt::Debug for HeaderSlice<H, T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("HeaderSlice")
+            .field("header", &self.header)
+            .field("slice", &self.slice())
+            .finish()
+    }
+}
+
+impl<H, T> HeaderSlice<H, T> {
+    /// Returns the dynamically sized slice in this HeaderSlice.
+    #[inline(always)]
+    pub fn slice(&self) -> &[T] {
+        unsafe { std::slice::from_raw_parts(self.data(), self.len) }
+    }
+
+    #[inline(always)]
+    fn data(&self) -> *const T {
+        std::ptr::addr_of!(self.data) as *const _
+    }
+
+    #[inline(always)]
+    fn data_mut(&mut self) -> *mut T {
+        std::ptr::addr_of_mut!(self.data) as *mut _
+    }
+
+    /// Returns the dynamically sized slice in this HeaderSlice.
+    #[inline(always)]
+    pub fn slice_mut(&mut self) -> &mut [T] {
+        unsafe { std::slice::from_raw_parts_mut(self.data_mut(), self.len) }
+    }
+
+    /// Returns the len of the slice.
+    #[inline(always)]
+    pub fn len(&self) -> usize {
+        self.len
+    }
+}
+
+impl<H, T> Arc<HeaderSlice<H, T>> {
+    /// Creates an Arc for a HeaderSlice using the given header struct and
+    /// iterator to generate the slice.
+    ///
+    /// `is_static` indicates whether to create a static Arc.
+    ///
+    /// `alloc` is used to get a pointer to the memory into which the
+    /// dynamically sized ArcInner<HeaderSlice<H, T>> value will be
+    /// written.  If `is_static` is true, then `alloc` must return a
+    /// pointer into some static memory allocation.  If it is false,
+    /// then `alloc` must return an allocation that can be dellocated
+    /// by calling Box::from_raw::<ArcInner<HeaderSlice<H, T>>> on it.
+    #[inline]
+    pub fn from_header_and_iter_alloc<F, I>(
+        alloc: F,
+        header: H,
+        mut items: I,
+        num_items: usize,
+        is_static: bool,
+    ) -> Self
+    where
+        F: FnOnce(Layout) -> *mut u8,
+        I: Iterator<Item = T>,
+    {
+        assert_ne!(size_of::<T>(), 0, "Need to think about ZST");
+
+        let layout = Layout::new::<ArcInner<HeaderSlice<H, T>>>();
+        debug_assert!(layout.align() >= align_of::<T>());
+        debug_assert!(layout.align() >= align_of::<usize>());
+        let array_layout = Layout::array::<T>(num_items).expect("Overflow");
+        let (layout, _offset) = layout.extend(array_layout).expect("Overflow");
+        let p = unsafe {
+            // Allocate the buffer.
+            let buffer = alloc(layout);
+            let mut p = ptr::NonNull::new(buffer)
+                .unwrap_or_else(|| alloc::handle_alloc_error(layout))
+                .cast::<ArcInner<HeaderSlice<H, T>>>();
+
+            // Write the data.
+            //
+            // Note that any panics here (i.e. from the iterator) are safe, since
+            // we'll just leak the uninitialized memory.
+            let count = if is_static {
+                atomic::AtomicUsize::new(STATIC_REFCOUNT)
+            } else {
+                atomic::AtomicUsize::new(1)
+            };
+            ptr::write(&mut p.as_mut().count, count);
+            #[cfg(feature = "track_alloc_size")]
+            ptr::write(&mut p.as_mut().alloc_size, layout.size());
+            ptr::write(&mut p.as_mut().data.header, header);
+            ptr::write(&mut p.as_mut().data.len, num_items);
+            if num_items != 0 {
+                let mut current = std::ptr::addr_of_mut!(p.as_mut().data.data) as *mut T;
+                for _ in 0..num_items {
+                    ptr::write(
+                        current,
+                        items
+                            .next()
+                            .expect("ExactSizeIterator over-reported length"),
+                    );
+                    current = current.offset(1);
+                }
+                // We should have consumed the buffer exactly, maybe accounting
+                // for some padding from the alignment.
+                debug_assert!(
+                    (buffer.add(layout.size()) as usize - current as *mut u8 as usize) < layout.align()
+                );
+            }
+            assert!(
+                items.next().is_none(),
+                "ExactSizeIterator under-reported length"
+            );
+            p
+        };
+        #[cfg(feature = "gecko_refcount_logging")]
+        unsafe {
+            if !is_static {
+                // FIXME(emilio): Would be so amazing to have
+                // std::intrinsics::type_name() around.
+                NS_LogCtor(p.as_ptr() as *mut _, b"ServoArc\0".as_ptr() as *const _, 8)
+            }
+        }
+
+        // Return the fat Arc.
+        assert_eq!(
+            size_of::<Self>(),
+            size_of::<usize>(),
+            "The Arc should be thin"
+        );
+
+        Arc {
+            p,
+            phantom: PhantomData,
+        }
+    }
+
+    /// Creates an Arc for a HeaderSlice using the given header struct and iterator to generate the
+    /// slice. Panics if num_items doesn't match the number of items.
+    #[inline]
+    pub fn from_header_and_iter_with_size<I>(header: H, items: I, num_items: usize) -> Self
+    where
+        I: Iterator<Item = T>,
+    {
+        Arc::from_header_and_iter_alloc(
+            |layout| unsafe { alloc::alloc(layout) },
+            header,
+            items,
+            num_items,
+            /* is_static = */ false,
+        )
+    }
+
+    /// Creates an Arc for a HeaderSlice using the given header struct and
+    /// iterator to generate the slice. The resulting Arc will be fat.
+    #[inline]
+    pub fn from_header_and_iter<I>(header: H, items: I) -> Self
+    where
+        I: Iterator<Item = T> + ExactSizeIterator,
+    {
+        let len = items.len();
+        Self::from_header_and_iter_with_size(header, items, len)
+    }
+}
+
+/// This is functionally equivalent to Arc<(H, [T])>
+///
+/// When you create an `Arc` containing a dynamically sized type like a slice, the `Arc` is
+/// represented on the stack as a "fat pointer", where the length of the slice is stored alongside
+/// the `Arc`'s pointer. In some situations you may wish to have a thin pointer instead, perhaps
+/// for FFI compatibility or space efficiency. `ThinArc` solves this by storing the length in the
+/// allocation itself, via `HeaderSlice`.
+pub type ThinArc<H, T> = Arc<HeaderSlice<H, T>>;
+
+/// See `ArcUnion`. This is a version that works for `ThinArc`s.
+pub type ThinArcUnion<H1, T1, H2, T2> = ArcUnion<HeaderSlice<H1, T1>, HeaderSlice<H2, T2>>;
+
+impl<H, T> UniqueArc<HeaderSlice<H, T>> {
+    #[inline]
+    pub fn from_header_and_iter<I>(header: H, items: I) -> Self
+    where
+        I: Iterator<Item = T> + ExactSizeIterator,
+    {
+        Self(Arc::from_header_and_iter(header, items))
+    }
+
+    #[inline]
+    pub fn from_header_and_iter_with_size<I>(header: H, items: I, num_items: usize) -> Self
+    where
+        I: Iterator<Item = T>,
+    {
+        Self(Arc::from_header_and_iter_with_size(
+            header, items, num_items,
+        ))
+    }
+
+    /// Returns a mutable reference to the header.
+    pub fn header_mut(&mut self) -> &mut H {
+        // We know this to be uniquely owned
+        unsafe { &mut (*self.0.ptr()).data.header }
+    }
+
+    /// Returns a mutable reference to the slice.
+    pub fn data_mut(&mut self) -> &mut [T] {
+        // We know this to be uniquely owned
+        unsafe { (*self.0.ptr()).data.slice_mut() }
+    }
+}
+
+/// A "borrowed `Arc`". This is a pointer to
+/// a T that is known to have been allocated within an
+/// `Arc`.
+///
+/// This is equivalent in guarantees to `&Arc<T>`, however it is
+/// a bit more flexible. To obtain an `&Arc<T>` you must have
+/// an `Arc<T>` instance somewhere pinned down until we're done with it.
+/// It's also a direct pointer to `T`, so using this involves less pointer-chasing
+///
+/// However, C++ code may hand us refcounted things as pointers to T directly,
+/// so we have to conjure up a temporary `Arc` on the stack each time.
+///
+/// `ArcBorrow` lets us deal with borrows of known-refcounted objects
+/// without needing to worry about where the `Arc<T>` is.
+#[derive(Debug, Eq, PartialEq)]
+pub struct ArcBorrow<'a, T: 'a>(&'a T);
+
+impl<'a, T> Copy for ArcBorrow<'a, T> {}
+impl<'a, T> Clone for ArcBorrow<'a, T> {
+    #[inline]
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<'a, T> ArcBorrow<'a, T> {
+    /// Clone this as an `Arc<T>`. This bumps the refcount.
+    #[inline]
+    pub fn clone_arc(&self) -> Arc<T> {
+        let arc = unsafe { Arc::from_raw(self.0) };
+        // addref it!
+        mem::forget(arc.clone());
+        arc
+    }
+
+    /// For constructing from a reference known to be Arc-backed,
+    /// e.g. if we obtain such a reference over FFI
+    #[inline]
+    pub unsafe fn from_ref(r: &'a T) -> Self {
+        ArcBorrow(r)
+    }
+
+    /// Compare two `ArcBorrow`s via pointer equality. Will only return
+    /// true if they come from the same allocation
+    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+        this.0 as *const T == other.0 as *const T
+    }
+
+    /// Temporarily converts |self| into a bonafide Arc and exposes it to the
+    /// provided callback. The refcount is not modified.
+    #[inline]
+    pub fn with_arc<F, U>(&self, f: F) -> U
+    where
+        F: FnOnce(&Arc<T>) -> U,
+        T: 'static,
+    {
+        // Synthesize transient Arc, which never touches the refcount.
+        let transient = unsafe { mem::ManuallyDrop::new(Arc::from_raw(self.0)) };
+
+        // Expose the transient Arc to the callback, which may clone it if it wants.
+        let result = f(&transient);
+
+        // Forward the result.
+        result
+    }
+
+    /// Similar to deref, but uses the lifetime |a| rather than the lifetime of
+    /// self, which is incompatible with the signature of the Deref trait.
+    #[inline]
+    pub fn get(&self) -> &'a T {
+        self.0
+    }
+}
+
+impl<'a, T> Deref for ArcBorrow<'a, T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &T {
+        self.0
+    }
+}
+
+/// A tagged union that can represent `Arc<A>` or `Arc<B>` while only consuming a
+/// single word. The type is also `NonNull`, and thus can be stored in an Option
+/// without increasing size.
+///
+/// This is functionally equivalent to
+/// `enum ArcUnion<A, B> { First(Arc<A>), Second(Arc<B>)` but only takes up
+/// up a single word of stack space.
+///
+/// This could probably be extended to support four types if necessary.
+pub struct ArcUnion<A, B> {
+    p: ptr::NonNull<()>,
+    phantom_a: PhantomData<A>,
+    phantom_b: PhantomData<B>,
+}
+
+unsafe impl<A: Sync + Send, B: Send + Sync> Send for ArcUnion<A, B> {}
+unsafe impl<A: Sync + Send, B: Send + Sync> Sync for ArcUnion<A, B> {}
+
+impl<A: PartialEq, B: PartialEq> PartialEq for ArcUnion<A, B> {
+    fn eq(&self, other: &Self) -> bool {
+        use crate::ArcUnionBorrow::*;
+        match (self.borrow(), other.borrow()) {
+            (First(x), First(y)) => x == y,
+            (Second(x), Second(y)) => x == y,
+            (_, _) => false,
+        }
+    }
+}
+
+impl<A: Eq, B: Eq> Eq for ArcUnion<A, B> {}
+
+/// This represents a borrow of an `ArcUnion`.
+#[derive(Debug)]
+pub enum ArcUnionBorrow<'a, A: 'a, B: 'a> {
+    First(ArcBorrow<'a, A>),
+    Second(ArcBorrow<'a, B>),
+}
+
+impl<A, B> ArcUnion<A, B> {
+    unsafe fn new(ptr: *mut ()) -> Self {
+        ArcUnion {
+            p: ptr::NonNull::new_unchecked(ptr),
+            phantom_a: PhantomData,
+            phantom_b: PhantomData,
+        }
+    }
+
+    /// Returns true if the two values are pointer-equal.
+    #[inline]
+    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+        this.p == other.p
+    }
+
+    #[inline]
+    pub fn ptr(&self) -> ptr::NonNull<()> {
+        self.p
+    }
+
+    /// Returns an enum representing a borrow of either A or B.
+    #[inline]
+    pub fn borrow(&self) -> ArcUnionBorrow<A, B> {
+        if self.is_first() {
+            let ptr = self.p.as_ptr() as *const ArcInner<A>;
+            let borrow = unsafe { ArcBorrow::from_ref(&(*ptr).data) };
+            ArcUnionBorrow::First(borrow)
+        } else {
+            let ptr = ((self.p.as_ptr() as usize) & !0x1) as *const ArcInner<B>;
+            let borrow = unsafe { ArcBorrow::from_ref(&(*ptr).data) };
+            ArcUnionBorrow::Second(borrow)
+        }
+    }
+
+    /// Creates an `ArcUnion` from an instance of the first type.
+    pub fn from_first(other: Arc<A>) -> Self {
+        let union = unsafe { Self::new(other.ptr() as *mut _) };
+        mem::forget(other);
+        union
+    }
+
+    /// Creates an `ArcUnion` from an instance of the second type.
+    pub fn from_second(other: Arc<B>) -> Self {
+        let union = unsafe { Self::new(((other.ptr() as usize) | 0x1) as *mut _) };
+        mem::forget(other);
+        union
+    }
+
+    /// Returns true if this `ArcUnion` contains the first type.
+    pub fn is_first(&self) -> bool {
+        self.p.as_ptr() as usize & 0x1 == 0
+    }
+
+    /// Returns true if this `ArcUnion` contains the second type.
+    pub fn is_second(&self) -> bool {
+        !self.is_first()
+    }
+
+    /// Returns a borrow of the first type if applicable, otherwise `None`.
+    pub fn as_first(&self) -> Option<ArcBorrow<A>> {
+        match self.borrow() {
+            ArcUnionBorrow::First(x) => Some(x),
+            ArcUnionBorrow::Second(_) => None,
+        }
+    }
+
+    /// Returns a borrow of the second type if applicable, otherwise None.
+    pub fn as_second(&self) -> Option<ArcBorrow<B>> {
+        match self.borrow() {
+            ArcUnionBorrow::First(_) => None,
+            ArcUnionBorrow::Second(x) => Some(x),
+        }
+    }
+}
+
+impl<A, B> Clone for ArcUnion<A, B> {
+    fn clone(&self) -> Self {
+        match self.borrow() {
+            ArcUnionBorrow::First(x) => ArcUnion::from_first(x.clone_arc()),
+            ArcUnionBorrow::Second(x) => ArcUnion::from_second(x.clone_arc()),
+        }
+    }
+}
+
+impl<A, B> Drop for ArcUnion<A, B> {
+    fn drop(&mut self) {
+        match self.borrow() {
+            ArcUnionBorrow::First(x) => unsafe {
+                let _ = Arc::from_raw(&*x);
+            },
+            ArcUnionBorrow::Second(x) => unsafe {
+                let _ = Arc::from_raw(&*x);
+            },
+        }
+    }
+}
+
+impl<A: fmt::Debug, B: fmt::Debug> fmt::Debug for ArcUnion<A, B> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self.borrow(), f)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Arc, ThinArc};
+    use std::clone::Clone;
+    use std::ops::Drop;
+    use std::sync::atomic;
+    use std::sync::atomic::Ordering::{Acquire, SeqCst};
+
+    #[derive(PartialEq)]
+    struct Canary(*mut atomic::AtomicUsize);
+
+    impl Drop for Canary {
+        fn drop(&mut self) {
+            unsafe {
+                (*self.0).fetch_add(1, SeqCst);
+            }
+        }
+    }
+
+    #[test]
+    fn empty_thin() {
+        let x = Arc::from_header_and_iter(100u32, std::iter::empty::<i32>());
+        assert_eq!(x.header, 100);
+        assert!(x.slice().is_empty());
+    }
+
+    #[test]
+    fn thin_assert_padding() {
+        #[derive(Clone, Default)]
+        #[repr(C)]
+        struct Padded {
+            i: u16,
+        }
+
+        // The header will have more alignment than `Padded`
+        let items = vec![Padded { i: 0xdead }, Padded { i: 0xbeef }];
+        let a = ThinArc::from_header_and_iter(0i32, items.into_iter());
+        assert_eq!(a.len(), 2);
+        assert_eq!(a.slice()[0].i, 0xdead);
+        assert_eq!(a.slice()[1].i, 0xbeef);
+    }
+
+    #[test]
+    fn slices_and_thin() {
+        let mut canary = atomic::AtomicUsize::new(0);
+        let c = Canary(&mut canary as *mut atomic::AtomicUsize);
+        let v = vec![5, 6];
+        {
+            let x = Arc::from_header_and_iter(c, v.into_iter());
+            let _ = x.clone();
+            let _ = x == x;
+        }
+        assert_eq!(canary.load(Acquire), 1);
+    }
+}
diff --git a/third_party/rust/cssparser/v0_27/BUILD.gn b/third_party/rust/cssparser/v0_27/BUILD.gn
index 530a336f4a81..309ec0126356 100644
--- a/third_party/rust/cssparser/v0_27/BUILD.gn
+++ b/third_party/rust/cssparser/v0_27/BUILD.gn
@@ -57,9 +57,13 @@ cargo_crate("lib") {
   ]
   build_root = "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.27.2/build.rs"
   build_sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.27.2/build.rs" ]
-  build_script_inputs = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.27.2/src/../build/match_byte.rs" ]
-  build_script_outputs = [ "tokenizer.rs" ]
   rustflags = [
     "--cap-lints=allow",  # Suppress all warnings in crates.io crates
   ]
+  if (epoch == "0.28" || epoch == "0.27") {
+    build_script_inputs =
+        [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-" +
+          cargo_pkg_version + "/build/match_byte.rs" ]
+    build_script_outputs = [ "tokenizer.rs" ]
+  }
 }
diff --git a/third_party/rust/cssparser/v0_28/BUILD.gn b/third_party/rust/cssparser/v0_28/BUILD.gn
index 34cb2998a123..4fefbb734e10 100644
--- a/third_party/rust/cssparser/v0_28/BUILD.gn
+++ b/third_party/rust/cssparser/v0_28/BUILD.gn
@@ -57,9 +57,13 @@ cargo_crate("lib") {
   ]
   build_root = "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.28.1/build.rs"
   build_sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.28.1/build.rs" ]
-  build_script_inputs = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.28.1/src/../build/match_byte.rs" ]
-  build_script_outputs = [ "tokenizer.rs" ]
   rustflags = [
     "--cap-lints=allow",  # Suppress all warnings in crates.io crates
   ]
+  if (epoch == "0.28" || epoch == "0.27") {
+    build_script_inputs =
+        [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-" +
+          cargo_pkg_version + "/build/match_byte.rs" ]
+    build_script_outputs = [ "tokenizer.rs" ]
+  }
 }
diff --git a/third_party/rust/cssparser/v0_34/BUILD.gn b/third_party/rust/cssparser/v0_34/BUILD.gn
new file mode 100644
index 000000000000..ac6ffc07bdcb
--- /dev/null
+++ b/third_party/rust/cssparser/v0_34/BUILD.gn
@@ -0,0 +1,61 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "cssparser"
+  epoch = "0.34"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/color.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/cow_rc_str.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/from_bytes.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/lib.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/macros.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/nth.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/parser.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/rules_and_declarations.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/serializer.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/size_of_tests.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tests.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/tokenizer.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/src/unicode_range.rs",
+  ]
+  inputs = []
+
+  build_native_rust_unit_tests = false
+  edition = "2018"
+  cargo_pkg_version = "0.34.0"
+  cargo_pkg_authors = "Simon Sapin <simon.sapin@exyr.org>"
+  cargo_pkg_name = "cssparser"
+  cargo_pkg_description = "Rust implementation of CSS Syntax Level 3"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [
+    "//brave/third_party/rust/cssparser_macros/v0_6:lib",
+    "//brave/third_party/rust/dtoa_short/v0_3:lib",
+    "//brave/third_party/rust/itoa/v1:lib",
+    "//brave/third_party/rust/phf/v0_11:lib",
+    "//brave/third_party/rust/smallvec/v1:lib",
+  ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+  if (epoch == "0.28" || epoch == "0.27") {
+    build_script_inputs =
+        [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-" +
+          cargo_pkg_version + "/build/match_byte.rs" ]
+    build_script_outputs = [ "tokenizer.rs" ]
+  }
+}
diff --git a/third_party/rust/cssparser/v0_34/README.chromium b/third_party/rust/cssparser/v0_34/README.chromium
new file mode 100644
index 000000000000..fa168b884a64
--- /dev/null
+++ b/third_party/rust/cssparser/v0_34/README.chromium
@@ -0,0 +1,10 @@
+Name: cssparser
+URL: https://crates.io/crates/cssparser
+Version: 0.34.0
+Revision: 5dc6d916a73159745e1fc1dd1f745e05d3130b0f
+License: Mozilla-Public-License-2.0
+License File: //brave/third_party/rust/chromium_crates_io/vendor/cssparser-0.34.0/LICENSE
+Shipped: yes
+Security Critical: yes
+
+Description: Rust implementation of CSS Syntax Level 3
diff --git a/third_party/rust/cssparser_macros/v0_6/BUILD.gn b/third_party/rust/cssparser_macros/v0_6/BUILD.gn
index ec6733edfe5a..f948eae37c0e 100644
--- a/third_party/rust/cssparser_macros/v0_6/BUILD.gn
+++ b/third_party/rust/cssparser_macros/v0_6/BUILD.gn
@@ -12,16 +12,16 @@ cargo_crate("lib") {
   crate_name = "cssparser_macros"
   epoch = "0.6"
   crate_type = "proc-macro"
-  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs"
-  sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/lib.rs" ]
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs"
+  sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/lib.rs" ]
   inputs = [
-    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo-checksum.json",
-    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/.cargo_vcs_info.json",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo-checksum.json",
+    "//brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/.cargo_vcs_info.json",
   ]
 
   build_native_rust_unit_tests = false
   edition = "2018"
-  cargo_pkg_version = "0.6.0"
+  cargo_pkg_version = "0.6.1"
   cargo_pkg_authors = "Simon Sapin <simon.sapin@exyr.org>"
   cargo_pkg_name = "cssparser-macros"
   cargo_pkg_description = "Procedural macros for cssparser"
@@ -33,7 +33,7 @@ cargo_crate("lib") {
   proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
   deps = [
     "//brave/third_party/rust/quote/v1:lib",
-    "//brave/third_party/rust/syn/v1:lib",
+    "//brave/third_party/rust/syn/v2:lib",
   ]
   rustflags = [
     "--cap-lints=allow",  # Suppress all warnings in crates.io crates
diff --git a/third_party/rust/cssparser_macros/v0_6/README.chromium b/third_party/rust/cssparser_macros/v0_6/README.chromium
index 6e10fe645c7e..a8b4d4fecce9 100644
--- a/third_party/rust/cssparser_macros/v0_6/README.chromium
+++ b/third_party/rust/cssparser_macros/v0_6/README.chromium
@@ -1,9 +1,9 @@
 Name: cssparser-macros
 URL: https://crates.io/crates/cssparser-macros
-Version: 0.6.0
-Revision: 65d6c3e0a5dc222f745dbc7bc16c92a49e3d2aff
+Version: 0.6.1
+Revision: 0ebd17bcd13808f087b083f34d2f816e380b5155
 License: Mozilla-Public-License-2.0
-License File: //brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.0/LICENSE
+License File: //brave/third_party/rust/chromium_crates_io/vendor/cssparser-macros-0.6.1/LICENSE
 Shipped: yes
 Security Critical: yes
 
diff --git a/third_party/rust/ego_tree/v0_10/BUILD.gn b/third_party/rust/ego_tree/v0_10/BUILD.gn
new file mode 100644
index 000000000000..3ad5ae790387
--- /dev/null
+++ b/third_party/rust/ego_tree/v0_10/BUILD.gn
@@ -0,0 +1,40 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "ego_tree"
+  epoch = "0.10"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/display.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/iter.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/lib.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/serde.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/src/sort.rs",
+  ]
+  inputs = []
+
+  build_native_rust_unit_tests = false
+  edition = "2021"
+  cargo_pkg_version = "0.10.0"
+  cargo_pkg_authors = "June McEnroe <june@causal.agency>, Carlo Federico Vescovo <vescovocarlofederico@gmail.com>"
+  cargo_pkg_name = "ego-tree"
+  cargo_pkg_description = "Vec-backed ID-tree"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+}
diff --git a/third_party/rust/ego_tree/v0_10/README.chromium b/third_party/rust/ego_tree/v0_10/README.chromium
new file mode 100644
index 000000000000..a385d03502f8
--- /dev/null
+++ b/third_party/rust/ego_tree/v0_10/README.chromium
@@ -0,0 +1,10 @@
+Name: ego-tree
+URL: https://crates.io/crates/ego-tree
+Version: 0.10.0
+Revision: a38b9c42cbf06049b2cc1859bfbf9d5895e4b018
+License: ISC
+License File: //brave/third_party/rust/chromium_crates_io/vendor/ego-tree-0.10.0/LICENSE
+Shipped: yes
+Security Critical: yes
+
+Description: Vec-backed ID-tree
diff --git a/third_party/rust/getopts/v0_2/BUILD.gn b/third_party/rust/getopts/v0_2/BUILD.gn
new file mode 100644
index 000000000000..8f76ff72f14f
--- /dev/null
+++ b/third_party/rust/getopts/v0_2/BUILD.gn
@@ -0,0 +1,38 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "getopts"
+  epoch = "0.2"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/lib.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/src/tests/mod.rs",
+  ]
+  inputs = []
+
+  build_native_rust_unit_tests = false
+  edition = "2015"
+  cargo_pkg_version = "0.2.21"
+  cargo_pkg_authors = "The Rust Project Developers"
+  cargo_pkg_name = "getopts"
+  cargo_pkg_description = "getopts-like option parsing."
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [ "//brave/third_party/rust/unicode_width/v0_1:lib" ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+}
diff --git a/third_party/rust/getopts/v0_2/README.chromium b/third_party/rust/getopts/v0_2/README.chromium
new file mode 100644
index 000000000000..bf873c997bbe
--- /dev/null
+++ b/third_party/rust/getopts/v0_2/README.chromium
@@ -0,0 +1,11 @@
+Name: getopts
+URL: https://crates.io/crates/getopts
+Version: 0.2.21
+Revision: be919b8323f57ba238ea9cd6e68190029809e278
+License: Apache-2.0
+License File: //brave/third_party/rust/chromium_crates_io/vendor/getopts-0.2.21/LICENSE-APACHE
+Shipped: yes
+Security Critical: yes
+
+Description: getopts-like option parsing.
+
diff --git a/third_party/rust/phf/v0_11/BUILD.gn b/third_party/rust/phf/v0_11/BUILD.gn
index dd7b8d8fc07e..4f04749f2983 100644
--- a/third_party/rust/phf/v0_11/BUILD.gn
+++ b/third_party/rust/phf/v0_11/BUILD.gn
@@ -36,8 +36,15 @@ cargo_crate("lib") {
   executable_configs += [ "//build/config/compiler:no_chromium_code" ]
   proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
   proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
-  deps = [ "//brave/third_party/rust/phf_shared/v0_11:lib" ]
-  features = [ "std" ]
+  deps = [
+    "//brave/third_party/rust/phf_macros/v0_11:lib",
+    "//brave/third_party/rust/phf_shared/v0_11:lib",
+  ]
+  features = [
+    "macros",
+    "phf_macros",
+    "std",
+  ]
   rustflags = [
     "--cap-lints=allow",  # Suppress all warnings in crates.io crates
   ]
diff --git a/third_party/rust/phf_macros/v0_11/BUILD.gn b/third_party/rust/phf_macros/v0_11/BUILD.gn
new file mode 100644
index 000000000000..466acbab7303
--- /dev/null
+++ b/third_party/rust/phf_macros/v0_11/BUILD.gn
@@ -0,0 +1,44 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "phf_macros"
+  epoch = "0.11"
+  crate_type = "proc-macro"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs"
+  sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/src/lib.rs" ]
+  inputs = []
+
+  build_native_rust_unit_tests = false
+  edition = "2021"
+  cargo_pkg_version = "0.11.3"
+  cargo_pkg_authors = "Steven Fackler <sfackler@gmail.com>"
+  cargo_pkg_name = "phf_macros"
+  cargo_pkg_description = "Macros to generate types in the phf crate"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [
+    "//brave/third_party/rust/phf_generator/v0_11:lib",
+    "//brave/third_party/rust/phf_shared/v0_11:lib",
+    "//brave/third_party/rust/proc_macro2/v1:lib",
+    "//brave/third_party/rust/quote/v1:lib",
+    "//brave/third_party/rust/syn/v2:lib",
+  ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+  if (epoch == "0.11") {
+    output_name = "phf_macros_v0_11"
+  }
+}
diff --git a/third_party/rust/phf_macros/v0_11/README.chromium b/third_party/rust/phf_macros/v0_11/README.chromium
new file mode 100644
index 000000000000..b8e4be9fd8bf
--- /dev/null
+++ b/third_party/rust/phf_macros/v0_11/README.chromium
@@ -0,0 +1,10 @@
+Name: phf_macros
+URL: https://crates.io/crates/phf_macros
+Version: 0.11.3
+Revision: 9b679189639fec8d449cd2f1759fad5dc0ef38db
+License: MIT
+License File: //brave/third_party/rust/chromium_crates_io/vendor/phf_macros-0.11.3/LICENSE
+Shipped: yes
+Security Critical: yes
+
+Description: Macros to generate types in the phf crate
diff --git a/third_party/rust/phf_macros/v0_8/BUILD.gn b/third_party/rust/phf_macros/v0_8/BUILD.gn
index 84529ecafd7c..fa494da0b7f9 100644
--- a/third_party/rust/phf_macros/v0_8/BUILD.gn
+++ b/third_party/rust/phf_macros/v0_8/BUILD.gn
@@ -39,4 +39,7 @@ cargo_crate("lib") {
   rustflags = [
     "--cap-lints=allow",  # Suppress all warnings in crates.io crates
   ]
+  if (epoch == "0.11") {
+    output_name = "phf_macros_v0_11"
+  }
 }
diff --git a/third_party/rust/scraper/v0_22/BUILD.gn b/third_party/rust/scraper/v0_22/BUILD.gn
new file mode 100644
index 000000000000..983e729458cf
--- /dev/null
+++ b/third_party/rust/scraper/v0_22/BUILD.gn
@@ -0,0 +1,64 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "scraper"
+  epoch = "0.22"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/element.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/mod.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/element_ref/serializable.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/error/utils.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/mod.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/serializable.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/html/tree_sink.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/lib.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/main.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/node/serializable.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selectable.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/selector.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/src/test.rs",
+  ]
+  inputs = []
+
+  build_native_rust_unit_tests = false
+  edition = "2021"
+  cargo_pkg_version = "0.22.0"
+  cargo_pkg_authors = "June McEnroe <june@causal.agency>"
+  cargo_pkg_name = "scraper"
+  cargo_pkg_description = "HTML parsing and querying with CSS selectors"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [
+    "//brave/third_party/rust/cssparser/v0_34:lib",
+    "//brave/third_party/rust/ego_tree/v0_10:lib",
+    "//brave/third_party/rust/getopts/v0_2:lib",
+    "//brave/third_party/rust/html5ever/v0_29:lib",
+    "//brave/third_party/rust/precomputed_hash/v0_1:lib",
+    "//brave/third_party/rust/selectors/v0_26:lib",
+    "//brave/third_party/rust/tendril/v0_4:lib",
+  ]
+  features = [
+    "errors",
+    "getopts",
+    "main",
+  ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+}
diff --git a/third_party/rust/scraper/v0_22/README.chromium b/third_party/rust/scraper/v0_22/README.chromium
new file mode 100644
index 000000000000..1cb414752b31
--- /dev/null
+++ b/third_party/rust/scraper/v0_22/README.chromium
@@ -0,0 +1,10 @@
+Name: scraper
+URL: https://crates.io/crates/scraper
+Version: 0.22.0
+Revision: dcf5e0c781f6b1d9a67b48ae0bdf551b04e9bc94
+License: ISC
+License File: //brave/third_party/rust/chromium_crates_io/vendor/scraper-0.22.0/LICENSE
+Shipped: yes
+Security Critical: yes
+
+Description: HTML parsing and querying with CSS selectors
diff --git a/third_party/rust/selectors/v0_26/BUILD.gn b/third_party/rust/selectors/v0_26/BUILD.gn
new file mode 100644
index 000000000000..1c64b4d70ec7
--- /dev/null
+++ b/third_party/rust/selectors/v0_26/BUILD.gn
@@ -0,0 +1,75 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "selectors"
+  epoch = "0.26"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/attr.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/bloom.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/builder.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/context.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/kleene_value.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/lib.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/matching.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/nth_index_cache.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/parser.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/cache.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/filter.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/relative_selector/mod.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/sink.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/tree.rs",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/visitor.rs",
+  ]
+  inputs = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo-checksum.json",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/.cargo_vcs_info.json",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/CHANGES.md",
+    "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/README.md",
+  ]
+
+  build_native_rust_unit_tests = false
+  edition = "2021"
+  cargo_pkg_version = "0.26.0"
+  cargo_pkg_authors = "The Servo Project Developers"
+  cargo_pkg_name = "selectors"
+  cargo_pkg_description = "CSS Selectors matching for Rust"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [
+    "//brave/third_party/rust/bitflags/v2:lib",
+    "//brave/third_party/rust/cssparser/v0_34:lib",
+    "//brave/third_party/rust/derive_more/v0_99:lib",
+    "//brave/third_party/rust/fxhash/v0_2:lib",
+    "//brave/third_party/rust/log/v0_4:lib",
+    "//brave/third_party/rust/new_debug_unreachable/v1:lib",
+    "//brave/third_party/rust/phf/v0_11:lib",
+    "//brave/third_party/rust/precomputed_hash/v0_1:lib",
+    "//brave/third_party/rust/servo_arc/v0_4:lib",
+    "//brave/third_party/rust/smallvec/v1:lib",
+  ]
+  aliased_deps = {
+    debug_unreachable = "//brave/third_party/rust/new_debug_unreachable/v1:lib"
+  }
+  build_deps = [ "//brave/third_party/rust/phf_codegen/v0_11:buildrs_support" ]
+  build_root = "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs"
+  build_sources = [ "//brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/build.rs" ]
+  build_script_outputs = [ "ascii_case_insensitive_html_attributes.rs" ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+}
diff --git a/third_party/rust/selectors/v0_26/README.chromium b/third_party/rust/selectors/v0_26/README.chromium
new file mode 100644
index 000000000000..705033135aae
--- /dev/null
+++ b/third_party/rust/selectors/v0_26/README.chromium
@@ -0,0 +1,10 @@
+Name: selectors
+URL: https://crates.io/crates/selectors
+Version: 0.26.0
+Revision: b73c5190f14cc570952b880432f65e3e7d7a31b6
+License: Mozilla-Public-License-2.0
+License File: //brave/third_party/rust/chromium_crates_io/vendor/selectors-0.26.0/../../../../../common/licenses/MPL-2.0
+Shipped: yes
+Security Critical: yes
+
+Description: CSS Selectors matching for Rust
diff --git a/third_party/rust/servo_arc/v0_4/BUILD.gn b/third_party/rust/servo_arc/v0_4/BUILD.gn
new file mode 100644
index 000000000000..26a62f1695d0
--- /dev/null
+++ b/third_party/rust/servo_arc/v0_4/BUILD.gn
@@ -0,0 +1,40 @@
+# Copyright 2023 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# @generated from third_party/rust/chromium_crates_io/BUILD.gn.hbs by
+# tools/crates/gnrt.
+# Do not edit!
+
+import("//build/rust/cargo_crate.gni")
+
+cargo_crate("lib") {
+  crate_name = "servo_arc"
+  epoch = "0.4"
+  crate_type = "rlib"
+  crate_root = "//brave/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs"
+  sources = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/lib.rs",
+  ]
+  inputs = [
+    "//brave/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo-checksum.json",
+    "//brave/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/.cargo_vcs_info.json",
+  ]
+
+  build_native_rust_unit_tests = false
+  edition = "2021"
+  cargo_pkg_version = "0.4.0"
+  cargo_pkg_authors = "The Servo Project Developers"
+  cargo_pkg_name = "servo_arc"
+  cargo_pkg_description = "A fork of std::sync::Arc with some extra functionality and without weak references"
+  library_configs -= [ "//build/config/compiler:chromium_code" ]
+  library_configs += [ "//build/config/compiler:no_chromium_code" ]
+  executable_configs -= [ "//build/config/compiler:chromium_code" ]
+  executable_configs += [ "//build/config/compiler:no_chromium_code" ]
+  proc_macro_configs -= [ "//build/config/compiler:chromium_code" ]
+  proc_macro_configs += [ "//build/config/compiler:no_chromium_code" ]
+  deps = [ "//brave/third_party/rust/stable_deref_trait/v1:lib" ]
+  rustflags = [
+    "--cap-lints=allow",  # Suppress all warnings in crates.io crates
+  ]
+}
diff --git a/third_party/rust/servo_arc/v0_4/README.chromium b/third_party/rust/servo_arc/v0_4/README.chromium
new file mode 100644
index 000000000000..7015ebb1df24
--- /dev/null
+++ b/third_party/rust/servo_arc/v0_4/README.chromium
@@ -0,0 +1,10 @@
+Name: servo_arc
+URL: https://crates.io/crates/servo_arc
+Version: 0.4.0
+Revision: eb13715da7ad499b54637d037aaa8ce7578dfdfc
+License: Apache-2.0
+License File: //brave/third_party/rust/chromium_crates_io/vendor/servo_arc-0.4.0/../../../../../common/licenses/Apache-2.0
+Shipped: yes
+Security Critical: yes
+
+Description: A fork of std::sync::Arc with some extra functionality and without weak references
diff --git a/third_party/rust/unicode_width/v0_1/BUILD.gn b/third_party/rust/unicode_width/v0_1/BUILD.gn
new file mode 100644
index 000000000000..98d9e64312a9
--- /dev/null
+++ b/third_party/rust/unicode_width/v0_1/BUILD.gn
@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+group("lib") {
+  public_deps = [ "//third_party/rust/unicode_width/v0_1:lib" ]
+}
diff --git a/third_party/rust/unicode_width/v0_1/README.chromium b/third_party/rust/unicode_width/v0_1/README.chromium
new file mode 100644
index 000000000000..4fc80d49b476
--- /dev/null
+++ b/third_party/rust/unicode_width/v0_1/README.chromium
@@ -0,0 +1,11 @@
+Name: unicode-width
+URL: https://crates.io/crates/unicode-width
+Version: 0.1.14
+License: Apache-2.0
+License File: //brave/third_party/rust/chromium_crates_io/vendor/unicode-width-0.1.14/../../../../../common/licenses/Apache-2.0
+Shipped: yes
+Security Critical: yes
+
+Description: Determine displayed width of `char` and `str` types
+according to Unicode Standard Annex #11 rules.
+