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

chrome/test/data/webui/test_api.js

Index: chrome/test/data/webui/test_api.js
diff --git a/chrome/test/data/webui/test_api.js b/chrome/test/data/webui/test_api.js
index be8664310a231be58f9744c91e67ac0f509155e3..0bb0e7ebe7a47c21ac38e25977a88771c9c3865a 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -44,6 +44,25 @@ var testing = {};
    */
   function Test() {};
 
+  /**
+   * Make all transitions and animations take 0ms.
+   * Any animations will still happen and webkitAnimationEnd should be
+   * listened to.

[Dan Beam, 2015/04/30 23:22:04]

Make all transitions and animations take 0ms. NOTE: this will completely disable
webkitTransitionEnd events. If your code relies on them firing, it will break.
webkitAnimationEnd events should still work.

[hcarmona, 2015/05/01 16:51:31]

Done.

+   * Transitions will not dispatch any webkitTransitionEnd events.
+   */
+  Test.disableAnimationsAndTransitions = function() {
+    var noAnimationStyle = document.createElement('style');
+    noAnimationStyle.id = 'no-animation';
+    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);
+  };
+
   Test.prototype = {
     /**
      * The name of the test.
@@ -306,6 +325,10 @@ var testing = {};
      * @type {Function}
      */
     tearDown: function() {
+      var noAnimationStyle = $('no-animation');
+      if (noAnimationStyle)
+        noAnimationStyle.parentNode.removeChild(noAnimationStyle);
+
       Mock4JS.verifyAllMocks();
     },