Disabling flaky test BackgroundTest.ForwardNavigationThroughIframes.

chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs

 // 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(['../../testing/chromevox_next_e2e_test_base.js',
              '../../testing/assert_additions.js']);
 
 GEN_INCLUDE(['../../testing/mock_feedback.js']);
 
@@ skipping 577 matching lines @@
         .expectSpeech('checked')
         .call(click)
         .expectSpeech('go')
         .expectSpeech('Check box')
         .expectSpeech('not checked')
         .replay();
   });
 });
 
 /** Tests navigating into and out of iframes.. */
-TEST_F('BackgroundTest', 'ForwardNavigationThroughIframes', function() {
+TEST_F('BackgroundTest', 'DISABLED_ForwardNavigationThroughIframes', function() {
   var mockFeedback = this.createMockFeedback();
 
   var runTestIfIframeIsLoaded = function(rootNode) {
     // Return if the iframe hasn't loaded yet.
     var iframe = rootNode.find({role: 'iframe'});
     var childDoc = iframe.firstChild;
     if (childDoc && childDoc.children.length == 0) {
       return;
     }
 
@@ skipping 14 matching lines @@
   this.runWithLoadedTree(this.iframesDoc, function(rootNode) {
     chrome.automation.getDesktop(function(desktopNode) {
       runTestIfIframeIsLoaded(rootNode);
 
       desktopNode.addEventListener('loadComplete', function(evt) {
         runTestIfIframeIsLoaded(rootNode);
       }, true);      
     });
   });
 });