Revert "Browser compat for window.requestAnimationFrame"

lib/dom/templates/html/frog/impl_Window.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class $CLASSNAME$EXTENDS$IMPLEMENTS native "@*DOMWindow" {
 
   _DocumentImpl get document() native "return this.document;";
 
   void requestLayoutFrame(TimeoutHandler callback) {
     _addMeasurementFrameCallback(callback);
   }
 
-  /** @domName DOMWindow.requestAnimationFrame */
-  int requestAnimationFrame(RequestAnimationFrameCallback callback) native '''
-    if (!window.requestAnimationFrame) {
-      window.requestAnimationFrame =
-          window.webkitRequestAnimationFrame ||
-          window.mozRequestAnimationFrame ||
-          window.msRequestAnimationFrame ||
-          window.oRequestAnimationFrame ||
-          function (callback) {
-            window.setTimeout(callback, 16 /* 16ms ~= 60fps */);
-          };
-    }
-    return window.requestAnimationFrame(callback);
-''';
-
-  // Protect member 'requestAnimationFrame'.
-  _requestAnimationFrame() native 'requestAnimationFrame';
-
 $!MEMBERS
 }