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..1657727c3267ab1778442ba0c9d2655394ee4c4c 100644
--- a/cc/animation/layer_animation_controller.h
+++ b/cc/animation/layer_animation_controller.h
@@ -40,7 +40,7 @@ class CC_EXPORT LayerAnimationController
   int id() const { return id_; }
 
   void AddAnimation(scoped_ptr<Animation> animation);
-  void PauseAnimation(int animation_id, double time_offset);
+  void PauseAnimation(int animation_id, base::TimeTicks time_offset);

[ajuma, 2014/04/09 17:37:39]

An offset seems more like a TimeDelta (a period of time) rather than a TimeTicks
(a point in time). That said, to avoid the double-to-TimeTicks-back-to-double
issue that Dana pointed out, I think you're better off leaving this as a double
in this CL and changing it to a TimeDelta in the CL where cc::Animation switches
from doubles to TimeTicks/TimeDeltas.

[Sikugu_, 2014/04/10 14:04:57]

Done.

   void RemoveAnimation(int animation_id);
   void RemoveAnimation(int animation_id,
                        Animation::TargetProperty target_property);
@@ -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,
@@ -134,6 +134,9 @@ class CC_EXPORT LayerAnimationController
   virtual ~LayerAnimationController();
 
  private:
+  double GetTimeTicks(base::TimeTicks time) {

[danakj, 2014/04/09 16:33:03]

make this a file-static method (or anon namespace) in the .cc file, and maybe
name something like TimeTicksToDoubleTime or something, to say you're not
returning a TimeTicks

[Sikugu_, 2014/04/10 14:04:57]

Done.

+    return (time - base::TimeTicks()).InSecondsF();
+  }
   typedef base::hash_set<int> TargetProperties;
 
   void PushNewAnimationsToImplThread(
@@ -143,15 +146,15 @@ 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 +179,7 @@ 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_;