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

cc/animation/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_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_
 #define CC_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
@@ skipping 22 matching lines @@
 class LayerAnimationValueProvider;
 
 class CC_EXPORT LayerAnimationController
     : public base::RefCounted<LayerAnimationController> {
  public:
   static scoped_refptr<LayerAnimationController> Create(int id);
 
   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);
   void AbortAnimations(Animation::TargetProperty target_property);
 
   // Ensures that the list of active animations on the main thread and the impl
   // thread are kept in sync. This function does not take ownership of the impl
   // thread controller. This method is virtual for testing.
   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,
                    AnimationEventsVector* events);
 
   // Returns the active animation in the given group, animating the given
   // property, if such an animation exists.
   Animation* GetAnimation(int group_id,
                           Animation::TargetProperty target_property) const;
 
@@ skipping 60 matching lines @@
   // animations. Returns false if the maximum scale cannot be computed.
   bool MaximumScale(float* max_scale) const;
 
  protected:
   friend class base::RefCounted<LayerAnimationController>;
 
   explicit LayerAnimationController(int id);
   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(
       LayerAnimationController* controller_impl) const;
   void RemoveAnimationsCompletedOnMainThread(
       LayerAnimationController* controller_impl) const;
   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,
     ForceActivation
   };
   void UpdateActivation(UpdateActivationType type);
 
   void NotifyObserversOpacityAnimated(float opacity);
   void NotifyObserversTransformAnimated(const gfx::Transform& transform);
   void NotifyObserversFilterAnimated(const FilterOperations& filter);
   void NotifyObserversScrollOffsetAnimated(const gfx::Vector2dF& scroll_offset);
 
   void NotifyObserversAnimationWaitingForDeletion();
 
   bool HasValueObserver();
   bool HasActiveValueObserver();
 
   AnimationRegistrar* registrar_;
   int id_;
   ScopedPtrVector<Animation> active_animations_;
 
   // 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_;
 
   LayerAnimationValueProvider* value_provider_;
 
   AnimationDelegate* layer_animation_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimationController);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_LAYER_ANIMATION_CONTROLLER_H_