Redirect cast extension chrome-extension:// URLs to regular API URL

ext/src/compat/youtube.js

@@ -8,3 +8,53 @@ document.addEventListener("beforescriptexecute", function onBeforeScriptExecute
     scriptElement.src = browser.runtime.getURL("vendor/webcomponents-lite.min.js");
     document.head.prepend(scriptElement);
 });
+
+
+const EXT_SENDER_SCRIPT_URLS = [
+    "chrome-extension://pkedcjkdefgpdelpbcmbmeomcjbeemfm/cast_sender.js"
+  , "chrome-extension://enhhojjnijigcajfphajepfemndkmdlo/cast_sender.js"
+];
+
+const SENDER_SCRIPT_URL = "https://www.gstatic.com/cv/js/sender/v1/cast_sender.js";
+
+
+// Store reference to original function
+const _createElement = document.createElement;
+
+function createElement () {
+    // Call original function
+    const element = _createElement.apply(this, arguments);
+
+    /**
+     * If the new element being created is a <script> element,
+     * replace the src property setter to intercept the new value.
+     *
+     * If it matches Chrome's cast extension sender script URL,
+     * replace it with the standard API URL, the request for which
+     * is handled in the main script.
+     */
+    if (element.nodeName === "SCRIPT") {
+        const { get, set } = Reflect.getOwnPropertyDescriptor(
+                Reflect.getPrototypeOf(element.wrappedJSObject), "src");
+
+        Reflect.defineProperty(element.wrappedJSObject, "src", {
+            configurable: true
+          , enumerable: true          
+          , get
+
+          , set: exportFunction(function (value) {
+                if (EXT_SENDER_SCRIPT_URLS.includes(value)) {
+                    return set.call(this, SENDER_SCRIPT_URL);
+                }
+                return set.call(this, value);
+            }, window)
+        });
+    }
+
+    return element;
+}
+
+// Redefine page's document.createElement function
+exportFunction(createElement, document, {
+    defineAs: "createElement"
+});