Revert "Changing return value of request animation frame."

lib/html/dart2js/html_dart2js.dart

Index: lib/html/dart2js/html_dart2js.dart
diff --git a/lib/html/dart2js/html_dart2js.dart b/lib/html/dart2js/html_dart2js.dart
index 475400ce077acba09acdb09cec4ea0c19b31e9f2..8bd9d5446fd09e64e68f9979ebb72d6b7b6a8924 100644
--- a/lib/html/dart2js/html_dart2js.dart
+++ b/lib/html/dart2js/html_dart2js.dart
@@ -22481,7 +22481,7 @@ class _RectImpl implements Rect native "*Rect" {
 
 // WARNING: Do not edit - generated code.
 
-typedef void RequestAnimationFrameCallback(int time);
+typedef bool RequestAnimationFrameCallback(int time);
 // 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.
@@ -35925,9 +35925,7 @@ class _WindowImpl extends _EventTargetImpl implements Window native "@*DOMWindow
    }
    if (this.requestAnimationFrame && this.cancelAnimationFrame) return;
    this.requestAnimationFrame = function(callback) {
-      return window.setTimeout(function() {
-        callback(Date.now());
-      }, 16 /* 16ms ~= 60fps */);
+       return window.setTimeout(callback, 16 /* 16ms ~= 60fps */);
    };
    this.cancelAnimationFrame = function(id) { clearTimeout(id); }
 ''';