cc: Make scheduling be driven by vsync for android webview.

content/browser/android/in_process/synchronous_compositor_impl.cc

Index: content/browser/android/in_process/synchronous_compositor_impl.cc
diff --git a/content/browser/android/in_process/synchronous_compositor_impl.cc b/content/browser/android/in_process/synchronous_compositor_impl.cc
index e76b36b85be6b0e5698c9c5d4e4b12d82f50ad7a..dcbccac9389c5061ea35490f97bf68f0aa09cc85 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.cc
+++ b/content/browser/android/in_process/synchronous_compositor_impl.cc
@@ -119,8 +119,9 @@ void SynchronousCompositorImpl::DidInitializeRendererObjects(
   output_surface_ = output_surface;
   begin_frame_source_ = begin_frame_source;
 
-  begin_frame_source_->SetCompositor(this);
-  output_surface_->SetBeginFrameSource(begin_frame_source_);
+  output_surface_->SetInvalidateCallback(
+      base::Bind(&SynchronousCompositorImpl::DidInvalidateOutputSurface,
+                 weak_ptr_factory_.GetWeakPtr()));
   output_surface_->SetTreeActivationCallback(
       base::Bind(&SynchronousCompositorImpl::DidActivatePendingTree,
                  weak_ptr_factory_.GetWeakPtr()));
@@ -133,7 +134,6 @@ void SynchronousCompositorImpl::DidDestroyRendererObjects() {
   DCHECK(begin_frame_source_);
 
   begin_frame_source_->SetCompositor(nullptr);
-  output_surface_->SetBeginFrameSource(nullptr);
   if (compositor_client_)
     compositor_client_->DidDestroyCompositor(this);
   compositor_client_ = nullptr;
@@ -183,6 +183,12 @@ scoped_ptr<cc::CompositorFrame> SynchronousCompositorImpl::DemandDrawHw(
 
   base::AutoReset<bool> invoking_composite_resetter(&invoking_composite_,
                                                     true);
+
+  // This is to handle draws that are not initiated by the platform.
+  // Platform draws happen synchronously after OnVSync is called.
+  if (!begin_frame_source_->InsideBeginFrame())
+    begin_frame_source_->SendBeginFrameNow();
+
   scoped_ptr<cc::CompositorFrame> frame =
       output_surface_->DemandDrawHw(surface_size,
                                     transform,
@@ -190,12 +196,12 @@ scoped_ptr<cc::CompositorFrame> SynchronousCompositorImpl::DemandDrawHw(
                                     clip,
                                     viewport_rect_for_tile_priority,
                                     transform_for_tile_priority);
+  
+  DCHECK(!begin_frame_source_->InsideBeginFrame());
+
   if (frame.get())
     UpdateFrameMetaData(frame->metadata);
 
-  compositor_client_->SetContinuousInvalidate(
-      begin_frame_source_->NeedsBeginFrames());
-
   return frame.Pass();
 }
 
@@ -214,14 +220,20 @@ bool SynchronousCompositorImpl::DemandDrawSw(SkCanvas* canvas) {
 
   base::AutoReset<bool> invoking_composite_resetter(&invoking_composite_,
                                                     true);
+ 
+  // This is to handle draws that are not initiated by the platform.
+  // Platform draws happen synchronously after OnVSync is called.
+  if (!begin_frame_source_->InsideBeginFrame())
+    begin_frame_source_->SendBeginFrameNow();
+
   scoped_ptr<cc::CompositorFrame> frame =
       output_surface_->DemandDrawSw(canvas);
+  
+  DCHECK(!begin_frame_source_->InsideBeginFrame());
+
   if (frame.get())
     UpdateFrameMetaData(frame->metadata);
 
-  compositor_client_->SetContinuousInvalidate(
-      begin_frame_source_->NeedsBeginFrames());
-
   return !!frame.get();
 }
 
@@ -241,11 +253,21 @@ void SynchronousCompositorImpl::SetMemoryPolicy(size_t bytes_limit) {
   output_surface_->SetMemoryPolicy(bytes_limit);
 }
 
+void SynchronousCompositorImpl::NeedsBeginFramesChanged() const {
+  compositor_client_->SetNeedsVSyncs(begin_frame_source_->NeedsBeginFrames());
+}
+
 void SynchronousCompositorImpl::DidChangeRootLayerScrollOffset() {
   if (input_handler_)
     input_handler_->OnRootLayerDelegatedScrollOffsetChanged();
 }
 
+void SynchronousCompositorImpl::OnVSync(base::TimeTicks frame_time, 
+      base::TimeDelta vsync_period) {
+  DCHECK(CalledOnValidThread());
+  begin_frame_source_->SendBeginFrame(frame_time, vsync_period);
+}
+
 void SynchronousCompositorImpl::SetInputHandler(
     cc::InputHandler* input_handler) {
   DCHECK(CalledOnValidThread());
@@ -275,18 +297,6 @@ void SynchronousCompositorImpl::DidStopFlinging() {
     rwhv->DidStopFlinging();
 }
 
-void SynchronousCompositorImpl::NeedsBeginFramesChanged() const {
-  DCHECK(CalledOnValidThread());
-  DCHECK(begin_frame_source_);
-  if (invoking_composite_)
-    return;
-
-  if (compositor_client_) {
-    compositor_client_->SetContinuousInvalidate(
-        begin_frame_source_->NeedsBeginFrames());
-  }
-}
-
 InputEventAckState SynchronousCompositorImpl::HandleInputEvent(
     const blink::WebInputEvent& input_event) {
   DCHECK(CalledOnValidThread());
@@ -305,6 +315,12 @@ void SynchronousCompositorImpl::DeliverMessages() {
   }
 }
 
+void SynchronousCompositorImpl::DidInvalidateOutputSurface() {
+  // Ignore invalidations while inside a draw.
+  if (compositor_client_ && !invoking_composite_)
+    compositor_client_->PostInvalidate();
+}
+
 void SynchronousCompositorImpl::DidActivatePendingTree() {
   if (compositor_client_)
     compositor_client_->DidUpdateContent();