feat: generate proguard rule file for android (#927)

* feat: generate proguard rule file for android

* remove `AppCompatActivity` from `proguard-wry.pro`

.changes/proguard.md

@@ -0,0 +1,5 @@
+---
+"wry": "patch"
+---
+
+On Android, generate a `proguard-wry.pro` file that could be used to keep the necessary symbols for wry when using minification.

build.rs

@@ -82,7 +82,18 @@ fn main() {
             &std::env::var(&class_init_env).unwrap_or_default(),
           );
 
-        let mut out = String::from("/* THIS FILE IS AUTO-GENERATED. DO NOT MODIFY!! */\n\n");
+        let auto_generated_comment = match file
+          .path()
+          .extension()
+          .unwrap_or_default()
+          .to_str()
+          .unwrap_or_default()
+        {
+          "pro" => "# THIS FILE IS AUTO-GENERATED. DO NOT MODIFY!!\n\n",
+          "kt" => "/* THIS FILE IS AUTO-GENERATED. DO NOT MODIFY!! */\n\n",
+          _ => "String::new()",
+        };
+        let mut out = String::from(auto_generated_comment);
         out.push_str(&content);
 
         fs::write(kotlin_out_dir.join(file.file_name()), out).expect("Failed to write kotlin file");

src/webview/android/kotlin/proguard-wry.pro

@@ -0,0 +1,36 @@
+# Copyright 2020-2023 Tauri Programme within The Commons Conservancy
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-License-Identifier: MIT
+
+-keep class {{package}}.* {
+  native <methods>;
+}
+
+-keep class {{package}}.WryActivity {
+  {{package}}.RustWebView m_webview;
+
+  public <init>(...);
+
+  void setM_webview({{package}}.RustWebView);
+  {{package}}.RustWebView getM_webview();
+
+  java.lang.Class getAppClass(...);
+  java.lang.String getVersion();
+}
+
+-keep class {{package}}.Ipc {
+  public <init>(...);
+
+  @android.webkit.JavascriptInterface public <methods>;
+}
+
+-keep class {{package}}.RustWebView {
+  public <init>(...);
+
+  void loadUrlMainThread(...);
+  void setAutoPlay(...);
+}
+
+-keep class {{package}}.RustWebChromeClient,{{package}}.RustWebViewClient {
+  public <init>(...);
+}