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 394da7515f64440971d8a4d61babae5b5ca5d293..5c60ffc40cb24a57e61ac69773e4f859beca0a86 100644
--- a/content/common/gpu/texture_image_transport_surface.h
+++ b/content/common/gpu/texture_image_transport_surface.h
@@ -19,6 +19,9 @@ class TextureImageTransportSurface :
     public GpuCommandBufferStub::DestructionObserver,
     public gfx::GLSurface {
  public:
+  enum { kMaxRequestReleaseFrontRetries = 10 };
+
+ public:
   TextureImageTransportSurface(GpuChannelManager* manager,
                                GpuCommandBufferStub* stub,
                                const gfx::GLSurfaceHandle& handle);
@@ -48,6 +51,10 @@ class TextureImageTransportSurface :
   virtual void OnBuffersSwappedACK() OVERRIDE;
   virtual void OnPostSubBufferACK() OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
+  virtual void OnSetFrontSurfaceIsProtected(bool is_protected) OVERRIDE;
+  virtual void OnRequestReleaseFrontACK(int request_id,
+                                        int retry_count,
+                                        bool was_released) OVERRIDE;
   virtual void OnResize(gfx::Size size) OVERRIDE;
 
   // GpuCommandBufferStub::DestructionObserver implementation.
@@ -74,9 +81,12 @@ class TextureImageTransportSurface :
 
   virtual ~TextureImageTransportSurface();
   void CreateBackTexture(const gfx::Size& size);
-  void ReleaseBackTexture();
   void AttachBackTextureToFBO();
+  void RequestReleaseFrontTexture(int retry_count);
+  void ReleaseTexture(int id);
   void ReleaseParentStub();
+  void AdjustFrontBufferAllocation(int retry_count);
+  int front() const { return front_; }
   int back() const { return 1 - front_; }
 
   // The framebuffer that represents this surface (service id). Allocated lazily
@@ -97,6 +107,11 @@ class TextureImageTransportSurface :
   bool backbuffer_suggested_allocation_;
   bool frontbuffer_suggested_allocation_;
 
+  bool frontbuffer_is_protected_;
+  bool ui_may_not_have_frontbuffer_handle_;
+  int current_valid_release_front_request_id_;
+  int next_unique_release_front_request_id_;
+
   scoped_ptr<ImageTransportHelper> helper_;
   GpuCommandBufferStub* parent_stub_;