Switch from chrome://extensions to chrome://settings/extensionSettings.

chrome/browser/resources/options/extension_settings.js

 // Copyright (c) 2011 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.
 
+// Used for observing function of the backend datasource for this page by
+// tests.
+var webui_responded_ = false;
+
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var ExtensionsList = options.ExtensionsList;
 
   /**
    * ExtensionSettings class
    * Encapsulated handling of the 'Manage Extensions' page.
    * @class
    */
   function ExtensionSettings() {
@@ skipping 121 matching lines @@
 
       chrome.send('extensionSettingsToggleDeveloperMode', []);
     },
   };
 
   /**
    * Called by the dom_ui_ to re-populate the page with data representing
    * the current state of installed extensions.
    */
   ExtensionSettings.returnExtensionsData = function(extensionsData) {
+    webui_responded_ = true;
+
     $('no-extensions').hidden = true;
     $('suggest-gallery').hidden = true;
     $('get-more-extensions-container').hidden = true;
 
     if (extensionsData.extensions.length > 0) {
       // Enforce order specified in the data or (if equal) then sort by
       // extension name (case-insensitive).
       extensionsData.extensions.sort(function(a, b) {
         if (a.order == b.order) {
           a = a.name.toLowerCase();
@@ skipping 14 matching lines @@
 
     var extensionList = $('extension-settings-list');
     ExtensionsList.decorate(extensionList);
   }
 
   // Export
   return {
     ExtensionSettings: ExtensionSettings
   };
 });