Ozone: Avoid blocking in Swapbuffer Call.

content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_COMPOSITOR_GPU_SURFACELESS_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 #define CONTENT_BROWSER_COMPOSITOR_GPU_SURFACELESS_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 
+#include "base/cancelable_callback.h"
 #include "content/browser/compositor/gpu_browser_compositor_output_surface.h"
 
 namespace content {
 
 class BufferQueue;
 class GLHelper;
 
 class GpuSurfacelessBrowserCompositorOutputSurface
     : public GpuBrowserCompositorOutputSurface {
  public:
   GpuSurfacelessBrowserCompositorOutputSurface(
       const scoped_refptr<ContextProviderCommandBuffer>& context,
       int surface_id,
       IDMap<BrowserCompositorOutputSurface>* output_surface_map,
       const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
       scoped_ptr<cc::OverlayCandidateValidator> overlay_candidate_validator,
       unsigned internalformat,
       bool use_own_gl_helper);
   ~GpuSurfacelessBrowserCompositorOutputSurface() override;
 
  private:
   // cc::OutputSurface implementation.
   void SwapBuffers(cc::CompositorFrame* frame) override;
   void OnSwapBuffersComplete() override;
   void BindFramebuffer() override;
   void Reshape(const gfx::Size& size, float scale_factor) override;
   bool BindToClient(cc::OutputSurfaceClient* client) override;
+  void OnPageFlipCompleted();
 
   unsigned int internalformat_;
   bool use_own_gl_helper_;
   scoped_ptr<GLHelper> gl_helper_;
   scoped_ptr<BufferQueue> output_surface_;
+  base::CancelableCallback<void()> page_flip_completion_callback_;

[alexst (slow to review), 2014/12/10 23:19:25]

Any specific reason you chose CancelableCallback?

 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_GPU_SURFACELESS_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_