Merge the Sky Engine changes from the SkyDart branch

sky/engine/core/animation/ElementAnimation.idl

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // http://www.w3.org/TR/web-animations/#idl-def-Element
 // FIXME: move to Animatable
 // http://dev.w3.org/fxtf/web-animations/#idl-def-Animatable
 
 partial interface Element {
     // FIXME: needs support for union types http://crbug.com/240176
     // AnimationPlayer animate((AnimationEffect or sequence<Dictionary>)? effect, optional (double or Dictionary) timing);
-    [Custom, RaisesException] AnimationPlayer animate(object effect, optional object timing);
+    // [Custom, RaisesException] AnimationPlayer animate(object effect, optional object timing);
     sequence<AnimationPlayer> getAnimationPlayers();
 };