[DevTools] Sanitize remoteFrontendUrl for old frontends.

third_party/WebKit/Source/devtools/front_end/devtools.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function(window) {
 
 // DevToolsAPI ----------------------------------------------------------------
 
 /**
  * @constructor
@@ skipping 946 matching lines @@
         for (var i = 0; i < properties.length; ++i)
             defineProperty(properties[i]);
     }
 
     window.Object.observe = objectObserve;
 }
 
 /**
  * @suppressGlobalPropertiesCheck
  */
+function sanitizeRemoteFrontendUrl()
+{
+    var queryParams = location.search;
+    if (!queryParams)
+        return;
+    var params = queryParams.substring(1).split("&");
+    for (var i = 0; i < params.length; ++i) {
+        var pair = params[i].split("=");
+        var name = pair.shift();
+        var value = pair.join("=");
+        if (name === "remoteFrontendUrl" && !value.startsWith("https://chrome-devtools-frontend.appspot.com/"))
+            location.search = "";
+    }
+}
+
+/**
+ * @suppressGlobalPropertiesCheck
+ */
 function installBackwardsCompatibility()
 {
+    sanitizeRemoteFrontendUrl();
+
     if (window.location.search.indexOf("remoteFrontend") === -1)
         return;
 
     // Support for legacy (<M50) frontends.
     installObjectObserve();
 
     /**
      * @this {CSSStyleDeclaration}
      */
     function getValue(property)
@@ skipping 35 matching lines @@
     // Support for legacy (<M49) frontends. Remove in M52.
     Event.prototype.deepPath = undefined;
 }
 
 function windowLoaded()
 {
     window.removeEventListener("DOMContentLoaded", windowLoaded, false);
     installBackwardsCompatibility();
 }
 
+sanitizeRemoteFrontendUrl();
 if (window.document.head && (window.document.readyState === "complete" || window.document.readyState === "interactive"))
     installBackwardsCompatibility();
 else
     window.addEventListener("DOMContentLoaded", windowLoaded, false);
 
 })(window);
 
 if (!DOMTokenList.prototype.__originalDOMTokenListToggle) {
     DOMTokenList.prototype.__originalDOMTokenListToggle = DOMTokenList.prototype.toggle;
     DOMTokenList.prototype.toggle = function(token, force)
     {
         if (arguments.length === 1)
             force = !this.contains(token);
         return this.__originalDOMTokenListToggle(token, !!force);
     }
 }