web: Inject plugin polyfill immediately, on chrome/edge

web/packages/extension/manifest_other.json5

@@ -48,6 +48,7 @@
         "storage",
         "webRequest",
         "declarativeNetRequest",
+        "scripting",
     ],
     "web_accessible_resources": [{
         "resources": ["*"],

web/packages/extension/src/background.ts

@@ -63,6 +63,24 @@ async function enable() {
             removeRuleIds: [RULE_SWF_URL],
             addRules: rules,
         });
+
+        await chrome.scripting.registerContentScripts([
+            {
+                id: "plugin-polyfill",
+                js: ["dist/pluginPolyfill.js"],
+                persistAcrossSessions: false,
+                matches: ["<all_urls>"],
+                excludeMatches: [
+                    "https://sso.godaddy.com/*",
+                    "https://authentication.td.com/*",
+                    "https://*.twitch.tv/*",
+                    "https://www.tuxedocomputers.com/*",
+                    "https://*.taobao.com/*",
+                ],
+                runAt: "document_start",
+                world: "MAIN",
+            },
+        ]);
     } else {
         (chrome || browser).webRequest.onHeadersReceived.addListener(
             onHeadersReceived,
@@ -80,6 +98,9 @@ async function disable() {
         await chrome.declarativeNetRequest.updateDynamicRules({
             removeRuleIds: [RULE_SWF_URL],
         });
+        await chrome.scripting.unregisterContentScripts({
+            ids: ["plugin-polyfill"],
+        });
     } else {
         (chrome || browser).webRequest.onHeadersReceived.removeListener(
             onHeadersReceived,

web/packages/extension/src/content.ts

@@ -142,15 +142,13 @@ function isXMLDocument(): boolean {
     }
 
     // We must run the plugin polyfill before any flash detection scripts.
-    // Unfortunately, this might still be too late for some websites when using Chrome (issue #969).
+    // Unfortunately, this might still be too late for some websites (issue #969).
     // NOTE: The script code injected here is the compiled form of
     // plugin-polyfill.ts. It is injected by tools/inject_plugin_polyfill.js
     // which just search-and-replaces for this particular string.
-    if (chrome) {
+    if (!chrome) {
-        await injectScriptURL(
+        // Chrome does this differently, by injecting it straight into the main world.
-            utils.runtime.getURL(`dist/pluginPolyfill.js?id=${ID}`),
+        // This isn't as fast, oh well.
-        );
-    } else {
         injectScriptRaw("%PLUGIN_POLYFILL_SOURCE%");
     }