Enable accelerated animations for orphaned layers

cc/layer_animation_value_observer.h

 // 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.
 
 #ifndef CC_LAYER_ANIMATION_VALUE_OBSERVER_H_
 #define CC_LAYER_ANIMATION_VALUE_OBSERVER_H_
 
 namespace cc {
 
 class CC_EXPORT LayerAnimationValueObserver {
  public:
   virtual ~LayerAnimationValueObserver() { }
 
   virtual void OnOpacityAnimated(float) = 0;
   virtual void OnTransformAnimated(const gfx::Transform&) = 0;
 
   virtual bool IsActive() const = 0;
+  virtual bool IsOrphaned() const = 0;
 };
 
 } // namespace cc
 
 #endif  // CC_LAYER_ANIMATION_VALUE_OBSERVER_H_