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

content/common/gpu/texture_image_transport_surface.h

Index: content/common/gpu/texture_image_transport_surface.h
diff --git a/content/common/gpu/texture_image_transport_surface.h b/content/common/gpu/texture_image_transport_surface.h
index ffc300a9691a6a92b1626f226091940a08f83925..6764fc31651694f487aa5f0ef3fde98b13b7ae05 100644
--- a/content/common/gpu/texture_image_transport_surface.h
+++ b/content/common/gpu/texture_image_transport_surface.h
@@ -48,6 +48,9 @@ class TextureImageTransportSurface :
   virtual void OnBufferPresented(
       uint32 sync_point) OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
+  virtual void OnSetFrontSurfaceIsProtected(
+      bool is_protected,
+      uint32 protection_state_id) OVERRIDE;
   virtual void OnResize(gfx::Size size) OVERRIDE;
 
   // GpuCommandBufferStub::DestructionObserver implementation.
@@ -74,10 +77,12 @@ class TextureImageTransportSurface :
 
   virtual ~TextureImageTransportSurface();
   void CreateBackTexture(const gfx::Size& size);
-  void ReleaseBackTexture();
   void AttachBackTextureToFBO();
+  void ReleaseTexture(int id);
   void ReleaseParentStub();
+  void AdjustFrontBufferAllocation();
   void BufferPresentedImpl();
+  int front() const { return front_; }
   int back() const { return 1 - front_; }
 
   // The framebuffer that represents this surface (service id). Allocated lazily
@@ -98,6 +103,9 @@ class TextureImageTransportSurface :
   bool backbuffer_suggested_allocation_;
   bool frontbuffer_suggested_allocation_;
 
+  bool frontbuffer_is_protected_;
+  uint32 protection_state_id_;
+
   scoped_ptr<ImageTransportHelper> helper_;
   gfx::GLSurfaceHandle handle_;
   GpuCommandBufferStub* parent_stub_;