Revert "Browser compat for window.requestAnimationFrame"

client/tests/client/dom/RequestAnimationFrameTest.dart

-// 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.
-
-#library('RequestAnimationFrameTest');
-#import('../../../../lib/unittest/unittest.dart');
-#import('../../../../lib/unittest/dom_config.dart');
-#import('dart:dom');
-
-main() {
-  useDomConfiguration();
-
-  asyncTest('oneShot', 1, () {
-      var frame = window.requestAnimationFrame(
-          (timestamp) { callbackDone(); });
-    });
-
-  asyncTest('twoShot', 1, () {
-      var frame = window.requestAnimationFrame(
-          (timestamp1) {
-            window.requestAnimationFrame(
-                (timestamp2) {
-                  Expect.isTrue(timestamp2 > timestamp1, 'timestamps ordered');
-                  callbackDone();
-                });
-          });
-    });
-}