CC should use TimeTicks and TimeDelta to represent time

cc/animation/layer_animation_controller.cc

Index: cc/animation/layer_animation_controller.cc
diff --git a/cc/animation/layer_animation_controller.cc b/cc/animation/layer_animation_controller.cc
index 464801ce92fb02a3803c27cfe2b837f4d066c1e5..207c34fbf97a17c7d2e095b71ddbb95f95f33695 100644
--- a/cc/animation/layer_animation_controller.cc
+++ b/cc/animation/layer_animation_controller.cc
@@ -24,7 +24,7 @@ LayerAnimationController::LayerAnimationController(int id)
     : registrar_(0),
       id_(id),
       is_active_(false),
-      last_tick_time_(0),
+      last_tick_time_(base::TimeTicks()),
       value_provider_(NULL),
       layer_animation_delegate_(NULL) {}
 
@@ -39,11 +39,13 @@ scoped_refptr<LayerAnimationController> LayerAnimationController::Create(
 }
 
 void LayerAnimationController::PauseAnimation(int animation_id,
-                                              double time_offset) {
+                                              base::TimeTicks time_offset) {
   for (size_t i = 0; i < active_animations_.size(); ++i) {
     if (active_animations_[i]->id() == animation_id) {
       active_animations_[i]->SetRunState(
-          Animation::Paused, time_offset + active_animations_[i]->start_time());
+          Animation::Paused,
+          (time_offset - base::TimeTicks()) +
+              active_animations_[i]->start_time());
     }
   }
 }
@@ -123,8 +125,8 @@ void LayerAnimationController::PushAnimationUpdatesTo(
   UpdateActivation(NormalActivation);
 }
 
-void LayerAnimationController::Animate(double monotonic_time) {
-  DCHECK(monotonic_time);
+void LayerAnimationController::Animate(base::TimeTicks monotonic_time) {
+  DCHECK(monotonic_time != base::TimeTicks());
   if (!HasValueObserver())
     return;
 
@@ -134,7 +136,7 @@ void LayerAnimationController::Animate(double monotonic_time) {
 }
 
 void LayerAnimationController::AccumulatePropertyUpdates(
-    double monotonic_time,
+    base::TimeTicks monotonic_time,
     AnimationEventsVector* events) {
   if (!events)
     return;
@@ -281,8 +283,7 @@ void LayerAnimationController::SetAnimationRegistrar(
 
 void LayerAnimationController::NotifyAnimationStarted(
     const AnimationEvent& event) {
-  base::TimeTicks monotonic_time = base::TimeTicks::FromInternalValue(
-      event.monotonic_time * base::Time::kMicrosecondsPerSecond);
+  base::TimeTicks monotonic_time = event.monotonic_time;
   if (event.is_impl_only) {
     FOR_EACH_OBSERVER(LayerAnimationEventObserver, event_observers_,
                       OnAnimationStarted(event));
@@ -314,8 +315,7 @@ void LayerAnimationController::NotifyAnimationStarted(
 
 void LayerAnimationController::NotifyAnimationFinished(
     const AnimationEvent& event) {
-  base::TimeTicks monotonic_time = base::TimeTicks::FromInternalValue(
-      event.monotonic_time * base::Time::kMicrosecondsPerSecond);
+  base::TimeTicks monotonic_time = event.monotonic_time;
   if (event.is_impl_only) {
     if (layer_animation_delegate_)
       layer_animation_delegate_->NotifyAnimationFinished(monotonic_time,
@@ -575,7 +575,7 @@ void LayerAnimationController::PushPropertiesToImplThread(
   }
 }
 
-void LayerAnimationController::StartAnimations(double monotonic_time) {
+void LayerAnimationController::StartAnimations(base::TimeTicks monotonic_time) {
   // First collect running properties.
   TargetProperties blocked_properties;
   for (size_t i = 0; i < active_animations_.size(); ++i) {
@@ -616,8 +616,8 @@ void LayerAnimationController::StartAnimations(double monotonic_time) {
         for (size_t j = i + 1; j < active_animations_.size(); ++j) {
           if (active_animations_[i]->group() ==
               active_animations_[j]->group()) {
-            active_animations_[j]->SetRunState(
-                Animation::Starting, monotonic_time);
+            active_animations_[j]->SetRunState(Animation::Starting,
+                                               monotonic_time);
           }
         }
       }
@@ -626,7 +626,7 @@ void LayerAnimationController::StartAnimations(double monotonic_time) {
 }
 
 void LayerAnimationController::PromoteStartedAnimations(
-    double monotonic_time,
+    base::TimeTicks monotonic_time,
     AnimationEventsVector* events) {
   for (size_t i = 0; i < active_animations_.size(); ++i) {
     if (active_animations_[i]->run_state() == Animation::Starting) {
@@ -648,7 +648,8 @@ void LayerAnimationController::PromoteStartedAnimations(
   }
 }
 
-void LayerAnimationController::MarkFinishedAnimations(double monotonic_time) {
+void LayerAnimationController::MarkFinishedAnimations(
+    base::TimeTicks monotonic_time) {
   for (size_t i = 0; i < active_animations_.size(); ++i) {
     if (active_animations_[i]->IsFinishedAt(monotonic_time) &&
         active_animations_[i]->run_state() != Animation::Aborted &&
@@ -658,7 +659,8 @@ void LayerAnimationController::MarkFinishedAnimations(double monotonic_time) {
 }
 
 void LayerAnimationController::MarkAnimationsForDeletion(
-    double monotonic_time, AnimationEventsVector* events) {
+    base::TimeTicks monotonic_time,
+    AnimationEventsVector* events) {
   bool marked_animations_for_deletions = false;
 
   // Non-aborted animations are marked for deletion after a corresponding
@@ -748,7 +750,7 @@ void LayerAnimationController::PurgeAnimationsMarkedForDeletion() {
                    animations.end());
 }
 
-void LayerAnimationController::TickAnimations(double monotonic_time) {
+void LayerAnimationController::TickAnimations(base::TimeTicks monotonic_time) {
   for (size_t i = 0; i < active_animations_.size(); ++i) {
     if (active_animations_[i]->run_state() == Animation::Starting ||
         active_animations_[i]->run_state() == Animation::Running ||