extension: Fix 4399 CORS and Flash detection issue (close #13943) (#16750)

Co-authored-by: Zhentao Lu <zhentaolu@microsoft.com>

web/packages/extension/4399_rules.json

@@ -0,0 +1,21 @@
+[
+  {
+    "id": 1,
+    "priority": 1,
+    "condition": {
+      "initiatorDomains": ["4399.com"],
+      "urlFilter": "|*.swf",
+      "resourceTypes": ["xmlhttprequest"]
+    },
+    "action": {
+      "type": "modifyHeaders",
+      "responseHeaders": [
+        {
+          "header": "Access-Control-Allow-Origin",
+          "operation": "set",
+          "value": "https://www.4399.com"
+        }
+      ]
+    }
+  }
+]

web/packages/extension/manifest_other.json5

@@ -28,6 +28,12 @@
             "js": ["dist/content.js"],
             "all_frames": true,
             "run_at": "document_start",
+        },
+        {
+            "matches": ["https://www.4399.com/flash/*"],
+            "js": ["dist/siteContentScript4399.js"],
+            "world": "MAIN",
+            "run_at": "document_start",
         }
     ],
 
@@ -50,11 +56,19 @@
     "permissions": [
         "storage",
         "scripting",
+        "declarativeNetRequest",
     ],
     "web_accessible_resources": [{
         "resources": ["*"],
         "matches": ["<all_urls>"],
     }],
+    "declarative_net_request": {
+        "rule_resources": [{
+            "id": "4399_rules",
+            "enabled": true,
+            "path": "dist/4399_rules.json"
+        }]
+    },
 
     // Chrome runs the extension in a single shared process by default,
     // which prevents extension pages from loading in Incognito tabs

web/packages/extension/src/4399-content-script.ts

@@ -0,0 +1,8 @@
+try {
+    Object.defineProperty(window, "showBlockFlash", {
+        value: () => {},
+        writable: false,
+    });
+} catch (e) {
+    // Ignore.
+}

web/packages/extension/webpack.config.js

@@ -85,6 +85,7 @@ export default function (/** @type {Record<string, any>} */ env, _argv) {
             background: "./src/background.ts",
             player: "./src/player.ts",
             pluginPolyfill: "./src/plugin-polyfill.ts",
+            siteContentScript4399: "./src/4399-content-script.ts",
         },
         output: {
             path: url.fileURLToPath(new URL("assets/dist/", import.meta.url)),
@@ -130,6 +131,7 @@ export default function (/** @type {Record<string, any>} */ env, _argv) {
                     },
                     { from: "LICENSE*" },
                     { from: "README.md" },
+                    { from: "4399_rules.json" },
                 ],
             }),
         ],