gfx: Add FrameTime and DisplayTime classes

ui/compositor/layer_animator.cc

Index: ui/compositor/layer_animator.cc
diff --git a/ui/compositor/layer_animator.cc b/ui/compositor/layer_animator.cc
index dd727a6c549458e3e9abbc326ec85aa7de2b0d98..2b5c1760e7c3b7726e6c0efe0e28233faedc1177 100644
--- a/ui/compositor/layer_animator.cc
+++ b/ui/compositor/layer_animator.cc
@@ -328,8 +328,8 @@ void LayerAnimator::OnThreadedAnimationStarted(
   if (!running->sequence()->waiting_for_group_start())
     return;
 
-  base::TimeTicks start_time = base::TimeTicks::FromInternalValue(
-      event.monotonic_time * base::Time::kMicrosecondsPerSecond);
+  gfx::FrameTime start_time =
+      gfx::FrameTime::Unsafe_FromSecondsF(event.monotonic_time);
 
   running->sequence()->set_waiting_for_group_start(false);
 
@@ -353,7 +353,7 @@ void LayerAnimator::OnThreadedAnimationStarted(
 // LayerAnimator protected -----------------------------------------------------
 
 void LayerAnimator::ProgressAnimation(LayerAnimationSequence* sequence,
-                                      base::TimeTicks now) {
+                                      gfx::FrameTime now) {
   if (!delegate() || sequence->waiting_for_group_start())
     return;
 
@@ -378,7 +378,7 @@ bool LayerAnimator::HasAnimation(LayerAnimationSequence* sequence) const {
 
 // LayerAnimator private -------------------------------------------------------
 
-void LayerAnimator::Step(base::TimeTicks now) {
+void LayerAnimator::Step(gfx::FrameTime now) {
   TRACE_EVENT0("ui", "LayerAnimator::Step");
   scoped_refptr<LayerAnimator> retain(this);
 
@@ -402,7 +402,7 @@ void LayerAnimator::Step(base::TimeTicks now) {
   }
 }
 
-void LayerAnimator::SetStartTime(base::TimeTicks start_time) {
+void LayerAnimator::SetStartTime(gfx::FrameTime start_time) {
   // Do nothing.
 }
 
@@ -764,7 +764,7 @@ bool LayerAnimator::StartSequenceImmediately(LayerAnimationSequence* sequence) {
   // All LayerAnimators share the same AnimationContainer. Use the
   // last_tick_time() from there to ensure animations started during the same
   // event complete at the same time.
-  base::TimeTicks start_time;
+  gfx::FrameTime start_time;
   if (is_animating() || adding_animations_)
     start_time = last_step_time_;
   else if (GetAnimationContainer()->is_running())