Test anonymous iframe in cross-origin-isolated context.

Instead of crashing, relax checks to allow anonymous iframe inside
cross-origin-isolated context.

Add a WPT test asking interesting questions about when the
cross-origin-isolated capability is delegated toward the anonymous
iframe (=open question).

In any case, the anonymous iframe must never be blocked, which this test
tests too.

Bug: 1237018
Change-Id: I973a98ccc58c7ee8399052a53ef2b2f3f5610f59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3074564
Commit-Queue: Camille Lamy <clamy@chromium.org>
Auto-Submit: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#910303}

html/cross-origin-embedder-policy/anonymous-iframe/cross-origin-isolated.tentative.window.js

@@ -0,0 +1,112 @@
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=../credentialless/resources/common.js
+// META: script=../credentialless/resources/dispatcher.js
+// META: timeout=long
+
+const same_origin = get_host_info().HTTPS_ORIGIN;
+const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
+
+const CROSS_ORIGIN_ISOLATED = "true";
+const NOT_CROSS_ORIGIN_ISOLATED = "false";
+const BLOCKED = "blocked";
+
+// Vary the headers of a parent and its anonymous iframe. Determine in which
+// cases the anonymous iframe gets the cross-origin-isolated capability.
+const crossOriginIsolatedTest = (description, params) => {
+  const default_params = {
+    parent_origin: same_origin,
+    parent_headers: '',
+    parent_allow: '',
+    child_origin: same_origin,
+    child_headers: '',
+    child_state: NOT_CROSS_ORIGIN_ISOLATED,
+  };
+  params = {...default_params, ...params};
+
+  promise_test_parallel(async test => {
+    // Create the parent.
+    const parent_token = token();
+    const parent_url = params.parent_origin + executor_path +
+        params.parent_headers + `&uuid=${parent_token}`;
+    const parent = window.open(parent_url)
+    add_completion_callback(() => parent.close());
+
+    // Create its anonymous iframe.
+    const child_token = token();
+    const child_url = params.child_origin + executor_path +
+        params.child_headers + `&uuid=${child_token}`;
+    send(parent_token, `
+      const iframe = document.createElement("iframe");
+      iframe.src = "${child_url}";
+      iframe.anonymous = true;
+      iframe.allow="${params.parent_allow}";
+      document.body.appendChild(iframe);
+    `);
+
+    // Check child's cross-origin isolation state.
+    const this_token = token();
+    send(child_token, `
+      send("${this_token}", window.crossOriginIsolated);
+    `);
+
+    test.step_timeout(() => {
+      send(this_token, 'blocked');
+    }, 3000);
+
+    assert_equals(await receive(this_token), params.child_state);
+  }, description);
+};
+
+crossOriginIsolatedTest("Basic", {
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Basic + child cross_origin", {
+  child_origin: cross_origin,
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Parent coep_require-corp", {
+  parent_headers: coep_require_corp,
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Parent coep_require-corp + cross_origin", {
+  parent_headers: coep_require_corp,
+  child_origin: cross_origin,
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Parent COI", {
+  parent_headers: coop_same_origin + coep_require_corp,
+  child_state: CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Parent COI + child cross-origin", {
+  parent_headers: coop_same_origin + coep_require_corp,
+  child_origin: cross_origin,
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest("Parent COI + child cross-origin COEP/CORP", {
+  parent_headers: coop_same_origin + coep_require_corp,
+  child_headers: coep_require_corp + corp_cross_origin,
+  child_origin: cross_origin,
+  child_state: NOT_CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest('Parent COI allow + child cross_origin', {
+  parent_headers: coop_same_origin + coep_require_corp,
+  parent_allow: 'cross-origin-isolated',
+  child_origin: cross_origin,
+  child_state: CROSS_ORIGIN_ISOLATED,
+});
+
+crossOriginIsolatedTest('Parent COI allow + child cross-origin COEP/CORP', {
+  parent_headers: coop_same_origin + coep_require_corp,
+  parent_allow: 'cross-origin-isolated',
+  child_headers: coep_require_corp + corp_cross_origin,
+  child_origin: cross_origin,
+  child_state: CROSS_ORIGIN_ISOLATED,
+});