webkitTransitionEnd is not triggered if property chane happens too fast

chrome/browser/resources/options/options_page.js

Index: chrome/browser/resources/options/options_page.js
diff --git a/chrome/browser/resources/options/options_page.js b/chrome/browser/resources/options/options_page.js
index befb7c813981bc869dfda9aa7f179a426fd178f3..303d16781074416a7f47c98f7ffc94e20870324d 100644
--- a/chrome/browser/resources/options/options_page.js
+++ b/chrome/browser/resources/options/options_page.js
@@ -887,11 +887,16 @@ cr.define('options', function() {
         // TODO(flackr): Use an event delegate to avoid having to subscribe and
         // unsubscribe for webkitTransitionEnd events.
         container.addEventListener('webkitTransitionEnd', function f(e) {
-            if (e.target != e.currentTarget || e.propertyName != 'opacity')
+            var propName = e.propertyName;
+            if (e.target != e.currentTarget ||
+                (propName && propName != 'opacity')) {
               return;
+            }
             container.removeEventListener('webkitTransitionEnd', f);
             self.fadeCompleted_();
         });
+        // -webkit-transition is 200ms. Let's wait for 400ms.
+        ensureTransitionEndEvent(container, 400);
       }
 
       if (visible) {