rAF: Introduce FrameRequestCallbackCollection for managing rAF callbacks.

Source/core/frame/Window.idl

Index: Source/core/frame/Window.idl
diff --git a/Source/core/frame/Window.idl b/Source/core/frame/Window.idl
index 486c3d878f36af041ff0ec44d5c36f25cc4ce956..a0ada4a13c5670bb7bdf50b8b2d92242aaa232b1 100644
--- a/Source/core/frame/Window.idl
+++ b/Source/core/frame/Window.idl
@@ -81,7 +81,7 @@
 
     // FIXME: requestAnimationFrame should take a FrameRequestCallback:
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=28152
-    [MeasureAs=UnprefixedRequestAnimationFrame] long requestAnimationFrame(RequestAnimationFrameCallback callback);
+    [MeasureAs=UnprefixedRequestAnimationFrame] long requestAnimationFrame(FrameRequestCallback callback);
     void cancelAnimationFrame(long handle);
 
     [DoNotCheckSecurity, Custom, RaisesException] void postMessage(any message, DOMString targetOrigin, optional sequence<Transferable> transfer);
@@ -166,7 +166,7 @@
     //  0 is straight up; -90 is when the device is rotated 90 clockwise;
     //  90 is when rotated counter clockwise.
     [MeasureAs=WindowOrientation, RuntimeEnabled=OrientationEvent] readonly attribute long orientation;
-    [DeprecateAs=PrefixedRequestAnimationFrame] long webkitRequestAnimationFrame(RequestAnimationFrameCallback callback);
+    [DeprecateAs=PrefixedRequestAnimationFrame] long webkitRequestAnimationFrame(FrameRequestCallback callback);
     [DeprecateAs=PrefixedCancelAnimationFrame, ImplementedAs=cancelAnimationFrame] void webkitCancelAnimationFrame(long id);
     [DeprecateAs=PrefixedCancelRequestAnimationFrame, ImplementedAs=cancelAnimationFrame] void webkitCancelRequestAnimationFrame(long id);
     [MeasureAs=PrefixedTransitionEventConstructor] attribute TransitionEventConstructor WebKitTransitionEvent;