Revert of Disable chromevox_tests BackgroundTest.InitialFeedback

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']);
 
 GEN_INCLUDE(['../../testing/mock_tts.js']);
 
 /**
@@ skipping 72 matching lines @@
     return null;
   }
 
   chrome.automation.getDesktop(function(root) {
     var testButton = findStatusTray(root);
     cvox.ChromeVox.tts.expectSpeech('Status tray', testDone);
     testButton.focus();
   });
 });
 
-// Flaky: http://crbug.com/451362
 /** Tests feedback once a page loads. */
-TEST_F('BackgroundTest', 'DISABLED_InitialFeedback', function() {
+TEST_F('BackgroundTest', 'InitialFeedback', function() {
   cvox.ChromeVox.tts.expectSpeech('start', function() {
     global.backgroundObj.onGotCommand('nextLine');
   }, true);
   cvox.ChromeVox.tts.expectSpeech('end', testDone, true);
 
   this.runWithDocument(function() {/*!
     <p>start
     <p>end
   */},
   function() {});
@@ skipping 86 matching lines @@
       }.bind(this), 0);
     }.bind(cvox.ChromeVox.tts);
 
     expect('start', doCmd('continuousRead'));
     expect('alpha Link', sendEndEvent);
     expect('beta Link', sendEndEvent);
     expect('Heading charlie', sendEndEvent);
     cvox.ChromeVox.tts.finishExpectations();
   }.bind(this));
 });