CC Animations: Make ui::LayerAnimator a LayerAnimationEventObserver (instead of ui::Layer)

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index 89562b97d66fe0a70b44944ccc46bd84867a32f6..2628fc131ca62357637fd9d8d78c5b57b5410c89 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -13,7 +13,6 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "cc/animation/animation_events.h"
-#include "cc/animation/layer_animation_event_observer.h"
 #include "cc/base/region.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer_client.h"
@@ -68,8 +67,7 @@ class COMPOSITOR_EXPORT Layer
     : public LayerAnimationDelegate,
       NON_EXPORTED_BASE(public cc::ContentLayerClient),
       NON_EXPORTED_BASE(public cc::TextureLayerClient),
-      NON_EXPORTED_BASE(public cc::LayerClient),
-      NON_EXPORTED_BASE(public cc::LayerAnimationEventObserver) {
+      NON_EXPORTED_BASE(public cc::LayerClient) {
  public:
   Layer();
   explicit Layer(LayerType type);
@@ -372,9 +370,6 @@ class COMPOSITOR_EXPORT Layer
   scoped_refptr<base::trace_event::ConvertableToTraceFormat> TakeDebugInfo(
       cc::Layer* layer) override;
 
-  // LayerAnimationEventObserver
-  void OnAnimationStarted(const cc::AnimationEvent& event) override;
-
   // Whether this layer has animations waiting to get sent to its cc::Layer.
   bool HasPendingThreadedAnimations() {
     return pending_threaded_animations_.size() != 0;
@@ -415,6 +410,7 @@ class COMPOSITOR_EXPORT Layer
   void AddThreadedAnimation(scoped_ptr<cc::Animation> animation) override;
   void RemoveThreadedAnimation(int animation_id) override;
   LayerAnimatorCollection* GetLayerAnimatorCollection() override;
+  cc::Layer* GetCcLayer() const override;
 
   // Creates a corresponding composited layer for |type_|.
   void CreateCcLayer();