Ozone: Avoid blocking in Swapbuffer Call.

content/common/gpu/image_transport_surface.h

Index: content/common/gpu/image_transport_surface.h
diff --git a/content/common/gpu/image_transport_surface.h b/content/common/gpu/image_transport_surface.h
index fea2d4f0980fa62df442a63ef31321247a03835a..340f4c5ccdd05a85ceb125739a7bd45ba732fc17 100644
--- a/content/common/gpu/image_transport_surface.h
+++ b/content/common/gpu/image_transport_surface.h
@@ -129,6 +129,8 @@ class ImageTransportHelper
 
   void SwapBuffersCompleted(const std::vector<ui::LatencyInfo>& latency_info);
 
+  void PageFlipCompleted();
+
   // Whether or not we should execute more commands.
   void SetScheduled(bool is_scheduled);
 
@@ -211,6 +213,7 @@ class PassThroughImageTransportSurface
   ImageTransportHelper* GetHelper() { return helper_.get(); }
 
  private:
+  void SwapBuffersCompleted();
   scoped_ptr<ImageTransportHelper> helper_;
   bool did_set_swap_interval_;
   std::vector<ui::LatencyInfo> latency_info_;