Fix ChromeVox next tests that passed without actually running.

chrome/browser/resources/chromeos/chromevox/testing/chromevox_next_e2e_test_base.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.
 
 // Include test fixture.
 GEN_INCLUDE(['chromevox_e2e_test_base.js']);
 
 /**
  * Base test fixture for ChromeVox Next end to end tests.
  *
  * These tests are identical to ChromeVoxE2ETests except for performing the
  * necessary setup to run ChromeVox Next.
  * @constructor
  * @extends {ChromeVoxE2ETest}
  */
 function ChromeVoxNextE2ETest() {
   ChromeVoxE2ETest.call(this);
 }
 
 ChromeVoxNextE2ETest.prototype = {
   __proto__: ChromeVoxE2ETest.prototype,
 
   /**
-   * Launches a new tab with the given document, and runs callback when a load
-   * complete fires.
+   * Gets the desktop from the automation API and Launches a new tab with
+   * the given document, and runs |callback| when a load complete fires.
+   * Arranges to call |testDone()| after |callback| returns.
+   * NOTE: Callbacks creatd instide |opt_callback| must be wrapped with
+   * |this.newCallback| if passed to asynchonous calls.  Otherwise, the test
+   * will be finished prematurely.
    * @param {function() : void} doc Snippet wrapped inside of a function.
-   * @param {function()} opt_callback Called once the document is ready.
+   * @param {function(chrome.automation.AutomationNode)} callback
+   *     Called once the document is ready.
    */
   runWithLoadedTree: function(doc, callback) {
     callback = this.newCallback(callback);
     chrome.automation.getDesktop(function(r) {
       var listener = function(evt) {
         if (!evt.target.docUrl ||
             evt.target.docUrl.indexOf('test') == -1)
           return;
 
         r.removeEventListener(listener);
         callback && callback(evt.target);
         callback = null;
       };
       r.addEventListener('loadComplete', listener, true);
       this.runWithTab(doc);
     }.bind(this));
   }
 };