Drop frontbuffers with ui-use-gpu-process, synchronized with browser, decoupled from backbuffer dro…

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 b6d8db48b285cc8d550adf916b2a1a617b8533f1..4cbad57d5db87652e0e5c56effdd2f1c17b2c458 100644
--- a/content/common/gpu/image_transport_surface.h
+++ b/content/common/gpu/image_transport_surface.h
@@ -62,6 +62,8 @@ class ImageTransportSurface {
   virtual void OnBufferPresented(uint32 sync_point) = 0;
   virtual void OnResizeViewACK() = 0;
   virtual void OnResize(gfx::Size size) = 0;
+  virtual void OnSetFrontSurfaceIsProtected(bool is_protected,
+                                            uint32 protection_state_id);
 
   // Creates the appropriate surface depending on the GL implementation.
   static scoped_refptr<gfx::GLSurface>
@@ -137,6 +139,8 @@ class ImageTransportHelper : public IPC::Listener {
   // IPC::Message handlers.
   void OnBufferPresented(uint32 sync_point);
   void OnResizeViewACK();
+  void OnSetFrontSurfaceIsProtected(bool is_protected,
+                                    uint32 protection_state_id);
 
   // Backbuffer resize callback.
   void Resize(gfx::Size size);