gfx: Add FrameTime and DisplayTime classes

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index eacd8b15f69a407dba52c7af3e6ced5da4648b60..388b62fc64f76f30f56a7a5851a59cd8ffd754c9 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -265,9 +265,9 @@ void LayerTreeHost::DidBeginMainFrame() {
   client_->DidBeginMainFrame();
 }
 
-void LayerTreeHost::UpdateClientAnimations(base::TimeTicks frame_begin_time) {
+void LayerTreeHost::UpdateClientAnimations(gfx::FrameTime frame_begin_time) {
   animating_ = true;
-  client_->Animate((frame_begin_time - base::TimeTicks()).InSecondsF());
+  client_->Animate(frame_begin_time.Unsafe_InSecondsF());
   animating_ = false;
 }
 
@@ -728,7 +728,7 @@ void LayerTreeHost::NotifyInputThrottledUntilCommit() {
   proxy_->NotifyInputThrottledUntilCommit();
 }
 
-void LayerTreeHost::Composite(base::TimeTicks frame_begin_time) {
+void LayerTreeHost::Composite(gfx::FrameTime frame_begin_time) {
   if (!proxy_->HasImplThread())
     static_cast<SingleThreadProxy*>(proxy_.get())->CompositeImmediately(
         frame_begin_time);
@@ -1191,14 +1191,14 @@ scoped_ptr<base::Value> LayerTreeHost::AsValue() const {
   return state.PassAs<base::Value>();
 }
 
-void LayerTreeHost::AnimateLayers(base::TimeTicks time) {
+void LayerTreeHost::AnimateLayers(gfx::FrameTime time) {
   if (!settings_.accelerated_animation_enabled ||
       animation_registrar_->active_animation_controllers().empty())
     return;
 
   TRACE_EVENT0("cc", "LayerTreeHost::AnimateLayers");
 
-  double monotonic_time = (time - base::TimeTicks()).InSecondsF();
+  double monotonic_time = time.Unsafe_InSecondsF();
 
   AnimationRegistrar::AnimationControllerMap copy =
       animation_registrar_->active_animation_controllers();