Enable tests related to the extensions web ui that were flaky.

chrome/test/data/webui/print_preview.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.
 
 /**
  * Test fixture for print preview WebUI testing.
  * @constructor
  * @extends {testing.Test}
  */
 function PrintPreviewWebUITest() {
@@ skipping 169 matching lines @@
       false /*selectionOnly*/,
       'FooDevice' /*systemDefaultDestinationId*/,
       null /*serializedAppStateStr*/,
       false /*documentHasSelection*/);
     this.localDestinationInfos_ = [
       { printerName: 'FooName', deviceName: 'FooDevice' },
       { printerName: 'BarName', deviceName: 'BarDevice' }
     ];
     this.nativeLayer_ = printPreview.nativeLayer_;
 
-    // Make all transitions and animations take 0ms for testing purposes.
-    // Animations still happen and must be waited on.
-    var noAnimationStyle = document.createElement('style');
-    noAnimationStyle.textContent =
-      '* {' +
-      '  -webkit-transition-duration: 0ms !important;' +
-      '  -webkit-transition-delay: 0ms !important;' +
-      '  -webkit-animation-duration: 0ms !important;' +
-      '  -webkit-animation-delay: 0ms !important;' +
-      '}';
-    document.querySelector('head').appendChild(noAnimationStyle);
+    testing.Test.disableAnimationsAndTransitions();
   }
 };
 
 GEN('#include "chrome/test/data/webui/print_preview.h"');
 
 // Test some basic assumptions about the print preview WebUI.
 TEST_F('PrintPreviewWebUITest', 'TestPrinterList', function() {
   this.setInitialSettings();
   this.setLocalDestinations();
 
@@ skipping 752 matching lines @@
   expectEquals(
       customLocalizedMediaName,
       mediaSelect.options[mediaSelect.selectedIndex].text);
   // Check the other media item.
   expectEquals(
       customMediaName,
       mediaSelect.options[mediaSelect.selectedIndex == 0 ? 1 : 0].text);
 
   this.waitForAnimationToEnd('more-settings');
 });