cc: Disallow scroll offset animations when impl-scrolling isn't supported

cc/animation/animation_registrar.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/animation/animation_registrar.h"
 
 #include "cc/animation/layer_animation_controller.h"
 
 namespace cc {
 
-AnimationRegistrar::AnimationRegistrar() {}
+AnimationRegistrar::AnimationRegistrar() : supports_scroll_animations_(false) {
+}
 
 AnimationRegistrar::~AnimationRegistrar() {
   AnimationControllerMap copy = all_animation_controllers_;
   for (AnimationControllerMap::iterator iter = copy.begin();
        iter != copy.end();
        ++iter)
     (*iter).second->SetAnimationRegistrar(NULL);
 }
 
 scoped_refptr<LayerAnimationController>
@@ skipping 26 matching lines @@
 }
 
 void AnimationRegistrar::UnregisterAnimationController(
     LayerAnimationController* controller) {
   if (ContainsKey(all_animation_controllers_, controller->id()))
     all_animation_controllers_.erase(controller->id());
   DidDeactivateAnimationController(controller);
 }
 
 }  // namespace cc