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 5fcd5d30b3d16d9a2703f67edcf02b98931f0f3f..02e505910a66669def88abd29faf566570e36229 100644
--- a/content/common/gpu/texture_image_transport_surface.h
+++ b/content/common/gpu/texture_image_transport_surface.h
@@ -36,7 +36,8 @@ class TextureImageTransportSurface :
   virtual unsigned int GetBackingFrameBufferObject() OVERRIDE;
   virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE;
   virtual bool OnMakeCurrent(gfx::GLContext* context) OVERRIDE;
-  virtual void SetBufferAllocation(BufferAllocationState state) OVERRIDE;
+  virtual void SetBackbufferAllocation(bool allocated) OVERRIDE;
+  virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
   virtual void* GetShareHandle() OVERRIDE;
   virtual void* GetDisplay() OVERRIDE;
   virtual void* GetConfig() OVERRIDE;
@@ -45,6 +46,7 @@ class TextureImageTransportSurface :
   // ImageTransportSurface implementation.
   virtual void OnNewSurfaceACK(
       uint64 surface_handle, TransportDIB::Handle shm_handle) OVERRIDE;
+  virtual void OnReleaseSurfaceACK(uint64 surface_id, bool success) OVERRIDE;
   virtual void OnBuffersSwappedACK() OVERRIDE;
   virtual void OnPostSubBufferACK() OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
@@ -69,10 +71,12 @@ class TextureImageTransportSurface :
   };
 
   virtual ~TextureImageTransportSurface();
-  void CreateBackTexture(const gfx::Size& size);
-  void ReleaseBackTexture();
-  void AttachBackTextureToFBO();
+  void CreateTexture(int id, const gfx::Size& size);
+  void RequestReleaseTexture(int id);
+  void ReleaseTexture(int id);
+  void AttachTextureToFBO(int id);
   gpu::gles2::TextureManager::TextureInfo* GetParentInfo(uint32 client_id);
+  int front() const { return front_; }
   int back() const { return 1 - front_; }
 
   // The framebuffer that represents this surface (service id). Allocated lazily
@@ -90,6 +94,9 @@ class TextureImageTransportSurface :
   // Whether or not the command buffer stub has been destroyed.
   bool stub_destroyed_;
 
+  bool backbuffer_allocated_;
+  bool frontbuffer_allocated_;
+
   scoped_ptr<ImageTransportHelper> helper_;
   base::WeakPtr<GpuCommandBufferStub> parent_stub_;