Moves RuntimeRebind classes out of the public interface.

Change-Id: If3cab423489172ce491bfff278519f214016380c
Adds missing @Override annotations.

Change-Id: Ia66b13f989c6ee97cd38ee4c259a6feaab774291
Update AnimationScheduler to use modern APIs

Change AnimationScheduler to start using requestAnimationFrame
on IE10, IE11, and any future browsers that have an unprefixed
requestAnimationFrame.
Chrome 24, Firefox 23 and IE10 already have a unprefixed versions.
Updated implementation to try unprefixed versions first,
then falling back to a polyfill using window.setTimeout.
Removed the need for rebinding due to the polyfill.

Change-Id: Ie00d1020285ce41c571054709bbe19aeef348975
merge from upstream