We don't want to tick animation controllers for non-active layers

cc/layer_animation_controller.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_CONTROLLER_H_
 #define CC_LAYER_ANIMATION_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
@@ skipping 91 matching lines @@
     void markAnimationsForDeletion(double monotonicTime, AnimationEventsVector*);
     void purgeAnimationsMarkedForDeletion();
 
     void tickAnimations(double monotonicTime);
 
     void updateActivation(bool force = false);
 
     void notifyObserversOpacityAnimated(float opacity);
     void notifyObserversTransformAnimated(const gfx::Transform& transform);
 
+    bool hasActiveObserver();
+
     // If this is true, we force a sync to the impl thread.
     bool m_forceSync;
 
     AnimationRegistrar* m_registrar;
     int m_id;
     ScopedPtrVector<ActiveAnimation> m_activeAnimations;
 
     // This is used to ensure that we don't spam the registrar.
     bool m_isActive;
 
     ObserverList<LayerAnimationValueObserver> m_observers;
 
     DISALLOW_COPY_AND_ASSIGN(LayerAnimationController);
 };
 
 } // namespace cc
 
 #endif  // CC_LAYER_ANIMATION_CONTROLLER_H_