CC::Animations should use TimeTicks & TimeDelta to represent time

cc/animation/layer_animation_controller.h

Index: cc/animation/layer_animation_controller.h
diff --git a/cc/animation/layer_animation_controller.h b/cc/animation/layer_animation_controller.h
index c5f0a3179af9f28c893f7c61641164d96e575040..b69bbb10536166311ed2ae9d36d5df8182b9259f 100644
--- a/cc/animation/layer_animation_controller.h
+++ b/cc/animation/layer_animation_controller.h
@@ -52,8 +52,8 @@ class CC_EXPORT LayerAnimationController
   virtual void PushAnimationUpdatesTo(
       LayerAnimationController* controller_impl);
 
-  void Animate(double monotonic_time);
-  void AccumulatePropertyUpdates(double monotonic_time,
+  void Animate(base::TimeTicks monotonic_time);
+  void AccumulatePropertyUpdates(base::TimeTicks monotonic_time,
                                  AnimationEventsVector* events);
 
   void UpdateState(bool start_ready_animations,
@@ -143,15 +143,15 @@ class CC_EXPORT LayerAnimationController
   void PushPropertiesToImplThread(
       LayerAnimationController* controller_impl) const;
 
-  void StartAnimations(double monotonic_time);
-  void PromoteStartedAnimations(double monotonic_time,
+  void StartAnimations(base::TimeTicks monotonic_time);
+  void PromoteStartedAnimations(base::TimeTicks monotonic_time,
                                 AnimationEventsVector* events);
-  void MarkFinishedAnimations(double monotonic_time);
-  void MarkAnimationsForDeletion(double monotonic_time,
+  void MarkFinishedAnimations(base::TimeTicks monotonic_time);
+  void MarkAnimationsForDeletion(base::TimeTicks monotonic_time,
                                  AnimationEventsVector* events);
   void PurgeAnimationsMarkedForDeletion();
 
-  void TickAnimations(double monotonic_time);
+  void TickAnimations(base::TimeTicks monotonic_time);
 
   enum UpdateActivationType {
     NormalActivation,
@@ -176,7 +176,7 @@ class CC_EXPORT LayerAnimationController
   // This is used to ensure that we don't spam the registrar.
   bool is_active_;
 
-  double last_tick_time_;
+  base::TimeTicks last_tick_time_;
 
   ObserverList<LayerAnimationValueObserver> value_observers_;
   ObserverList<LayerAnimationEventObserver> event_observers_;