compositor: Tick the UI animations from cc, instead of from timer callbacks.

ui/compositor/layer_animator.h

Index: ui/compositor/layer_animator.h
diff --git a/ui/compositor/layer_animator.h b/ui/compositor/layer_animator.h
index a1e0ad2cd44a382a043d4e4de757ef5adf716e33..d8fb88cf3dcc401912b1132a2d74a9db96895a13 100644
--- a/ui/compositor/layer_animator.h
+++ b/ui/compositor/layer_animator.h
@@ -15,7 +15,6 @@
 #include "base/time/time.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/layer_animation_element.h"
-#include "ui/gfx/animation/animation_container_element.h"
 #include "ui/gfx/animation/tween.h"
 
 namespace gfx {
@@ -40,9 +39,7 @@ class ScopedLayerAnimationSettings;
 // ensure that it is not disposed of until it finishes executing. It does this
 // by holding a reference to itself for the duration of methods for which it
 // must guarantee that |this| is valid.
-class COMPOSITOR_EXPORT LayerAnimator
-    : public gfx::AnimationContainerElement,
-      public base::RefCounted<LayerAnimator> {
+class COMPOSITOR_EXPORT LayerAnimator : public base::RefCounted<LayerAnimator> {
  public:
   enum PreemptionStrategy {
     IMMEDIATELY_SET_NEW_TARGET,
@@ -188,6 +185,8 @@ class COMPOSITOR_EXPORT LayerAnimator
   }
   base::TimeTicks last_step_time() const { return last_step_time_; }
 
+  void Step(base::TimeTicks time_now);
+
  protected:
   virtual ~LayerAnimator();
 
@@ -225,11 +224,6 @@ class COMPOSITOR_EXPORT LayerAnimator
   typedef std::vector<RunningAnimation> RunningAnimations;
   typedef std::deque<linked_ptr<LayerAnimationSequence> > AnimationQueue;
 
-  // Implementation of AnimationContainerElement
-  virtual void SetStartTime(base::TimeTicks start_time) OVERRIDE;
-  virtual void Step(base::TimeTicks time_now) OVERRIDE;
-  virtual base::TimeDelta GetTimerInterval() const OVERRIDE;
-
   // Finishes all animations by either advancing them to their final state or by
   // aborting them.
   void StopAnimatingInternal(bool abort);