Enable a11y audit for chrome://settings

chrome/browser/ui/webui/options/content_options_browsertest.js

 // Copyright (c) 2012 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.
 
+GEN_INCLUDE(['options_browsertest_base.js']);
+
 /**
  * TestFixture for content options WebUI testing.
  * @extends {testing.Test}
  * @constructor
  */
 function ContentOptionsWebUITest() {}
 
 ContentOptionsWebUITest.prototype = {
-  __proto__: testing.Test.prototype,
+  __proto__: OptionsBrowsertestBase.prototype,
 
   /**
    * Browse to content options.
+   * @override
    */
   browsePreload: 'chrome://settings-frame/content',
 };
 
 // Test opening the content options has correct location.
 TEST_F('ContentOptionsWebUITest', 'testOpenContentOptions', function() {
   assertEquals(this.browsePreload, document.location.href);
 });