Ozone: Avoid blocking in Swapbuffer Call.

content/common/gpu/image_transport_surface.cc

Index: content/common/gpu/image_transport_surface.cc
diff --git a/content/common/gpu/image_transport_surface.cc b/content/common/gpu/image_transport_surface.cc
index 02a6af0147f4dcdb7f5de651b6a38dbb154a1cbf..a61448c8450ff9274b4557edf104b4650e12348d 100644
--- a/content/common/gpu/image_transport_surface.cc
+++ b/content/common/gpu/image_transport_surface.cc
@@ -125,6 +125,10 @@ void ImageTransportHelper::SwapBuffersCompleted(
   stub_->SwapBuffersCompleted(latency_info);
 }
 
+void ImageTransportHelper::PageFlipCompleted() {
+  stub_->PageFlipCompleted();
+}
+
 void ImageTransportHelper::SetScheduled(bool is_scheduled) {
   gpu::GpuScheduler* scheduler = Scheduler();
   if (!scheduler)
@@ -214,6 +218,9 @@ PassThroughImageTransportSurface::PassThroughImageTransportSurface(
                                          manager,
                                          stub,
                                          gfx::kNullPluginWindow));
+  GLSurfaceAdapter::SetPageFlipCompletionCallback(
+      base::Bind(&ImageTransportHelper::PageFlipCompleted,
+          helper_->AsWeakPtr()));
 }
 
 bool PassThroughImageTransportSurface::Initialize() {