Fixing TransitionEnd event.

tools/dom/templates/html/impl/impl_Element.darttemplate

Index: tools/dom/templates/html/impl/impl_Element.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Element.darttemplate b/tools/dom/templates/html/impl/impl_Element.darttemplate
index 890938e44e0282eaaf56fb24a38ad0ed09b0bb9f..3f7757118294bd61bad18f0df57f535dc5400d6d 100644
--- a/tools/dom/templates/html/impl/impl_Element.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Element.darttemplate
@@ -770,6 +770,7 @@ $endif
   var xtag;
 
 $if DART2JS
+  @DomName('Element.mouseWheelEvent')
   static const EventStreamProvider<WheelEvent> mouseWheelEvent =
       const _CustomEventStreamProvider<WheelEvent>(
         Element._determineMouseWheelEventType);
@@ -787,6 +788,20 @@ $if DART2JS
     }
   }
 
+  @DomName('Element.webkitTransitionEndEvent')
+  static const EventStreamProvider<TransitionEvent> transitionEndEvent =
+      const _CustomEventStreamProvider<TransitionEvent>(
+        Element._determineTransitionEventType);
+
+  static String _determineTransitionEventType(EventTarget e) {
+    // Unfortunately the normal 'ontransitionend' style checks don't work here.
+    if (_Device.isWebKit) {
+      return 'webkitTransitionEnd';
+    } else if (_Device.isOpera) {
+      return 'oTransitionEnd';
+    }
+    return 'transitionend';
+  }
   /**
    * Creates a text node and inserts it into the DOM at the specified location.
    *