Change LayerHostImpl to use frame time from BeginFrameArgs rather than ::Now()

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 58e89b01b27a940f573df6a10a5db8d393fb0f92..a19d5e685adf6eeaa3268df589210f3dd496951b 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -454,10 +454,6 @@ void ThreadProxy::BeginImplFrame(const BeginFrameArgs& args) {
   TRACE_EVENT0("cc", "ThreadProxy::BeginImplFrame");
   DCHECK(IsImplThread());
 
-  // Sample the frame time now. This time will be used for updating animations
-  // when we draw.
-  impl().layer_tree_host_impl->CurrentFrameTimeTicks();
-
   impl().scheduler->BeginImplFrame(args);
 }
 
@@ -771,7 +767,7 @@ void ThreadProxy::ScheduledActionSendBeginMainFrame() {
   scoped_ptr<BeginMainFrameAndCommitState> begin_main_frame_state(
       new BeginMainFrameAndCommitState);
   begin_main_frame_state->monotonic_frame_begin_time =
-      impl().layer_tree_host_impl->CurrentPhysicalTimeTicks();
+      impl().layer_tree_host_impl->CurrentFrameTimeTicks();
   begin_main_frame_state->scroll_info =
       impl().layer_tree_host_impl->ProcessScrollDeltas();
 
@@ -1392,7 +1388,6 @@ void ThreadProxy::PostBeginImplFrameDeadline(const base::Closure& closure,
 }
 
 void ThreadProxy::DidBeginImplFrameDeadline() {

[danakj, 2014/03/11 18:32:36]

Can this method go away?

-  impl().layer_tree_host_impl->ResetCurrentFrameTimeForNextFrame();
 }
 
 void ThreadProxy::ReadyToFinalizeTextureUpdates() {
@@ -1631,7 +1626,7 @@ void ThreadProxy::RenewTreePriority() {
       impl().layer_tree_host_impl->IsCurrentlyScrolling() ||
       impl().layer_tree_host_impl->page_scale_animation_active();
 
-  base::TimeTicks now = impl().layer_tree_host_impl->CurrentPhysicalTimeTicks();
+  base::TimeTicks now = gfx::FrameTime::Now();

[danakj, 2014/03/11 18:32:36]

Why are you using Now here?

 
   // Update expiration time if smoothness currently takes priority.
   if (smoothness_takes_priority) {