gfx: Add FrameTime and DisplayTime classes

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 93b91311e6e94c9f821ad8753cbe56d40d6b27b4..2770aa8f7cbbdff3b2126b4bfd3d85cd36bdd791 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -117,22 +117,24 @@ void Scheduler::DidCreateAndInitializeOutputSurface() {
   ProcessScheduledActions();
 }
 
-base::TimeTicks Scheduler::AnticipatedDrawTime() {
+gfx::FrameTime Scheduler::AnticipatedDrawTime() {
   TRACE_EVENT0("cc", "Scheduler::AnticipatedDrawTime");
 
   if (!last_set_needs_begin_impl_frame_ ||
       last_begin_impl_frame_args_.interval <= base::TimeDelta())
-    return base::TimeTicks();
+    return gfx::FrameTime();
 
-  base::TimeTicks now = gfx::FrameTime::Now();
-  base::TimeTicks timebase = std::max(last_begin_impl_frame_args_.frame_time,
-                                      last_begin_impl_frame_args_.deadline);
+  gfx::FrameTime now = gfx::FrameTime::Now();
+  gfx::FrameTime timebase =
+      std::max<gfx::FrameTime>(
+          last_begin_impl_frame_args_.frame_time,
+          last_begin_impl_frame_args_.deadline);
   int64 intervals =
       1 + ((now - timebase) / last_begin_impl_frame_args_.interval);
   return timebase + (last_begin_impl_frame_args_.interval * intervals);
 }
 
-base::TimeTicks Scheduler::LastBeginImplFrameTime() {
+gfx::FrameTime Scheduler::LastBeginImplFrameTime() {
   return last_begin_impl_frame_args_.frame_time;
 }
 
@@ -182,7 +184,8 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
          SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
   DCHECK(state_machine_.HasInitializedOutputSurface());
   last_begin_impl_frame_args_ = args;
-  last_begin_impl_frame_args_.deadline -= client_->DrawDurationEstimate();
+  last_begin_impl_frame_args_.deadline =
+      last_begin_impl_frame_args_.deadline - client_->DrawDurationEstimate();
   state_machine_.OnBeginImplFrame(last_begin_impl_frame_args_);
   ProcessScheduledActions();
 
@@ -201,10 +204,10 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   } else if (!settings_.deadline_scheduling_enabled) {
     // We emulate the old non-deadline scheduler here by posting the
     // deadline task without any delay.
-    PostBeginImplFrameDeadline(base::TimeTicks());
+    PostBeginImplFrameDeadline(gfx::FrameTime());
   } else if (state_machine_.ShouldTriggerBeginImplFrameDeadlineEarly()) {
     // We are ready to draw a new active tree immediately.
-    PostBeginImplFrameDeadline(base::TimeTicks());
+    PostBeginImplFrameDeadline(gfx::FrameTime());
   } else if (state_machine_.needs_redraw()) {
     // We have an animation or fast input path on the impl thread that wants
     // to draw, so don't wait too long for a new active tree.
@@ -222,7 +225,7 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   }
 }
 
-void Scheduler::PostBeginImplFrameDeadline(base::TimeTicks deadline) {
+void Scheduler::PostBeginImplFrameDeadline(gfx::FrameTime deadline) {
   begin_impl_frame_deadline_closure_.Cancel();
   begin_impl_frame_deadline_closure_.Reset(
       base::Bind(&Scheduler::OnBeginImplFrameDeadline,
@@ -337,7 +340,7 @@ void Scheduler::ProcessScheduledActions() {
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 
   if (state_machine_.ShouldTriggerBeginImplFrameDeadlineEarly())
-    PostBeginImplFrameDeadline(base::TimeTicks());
+    PostBeginImplFrameDeadline(gfx::FrameTime());
 }
 
 bool Scheduler::WillDrawIfNeeded() const {