cc: Make most of cc::OutputSurface abstract.

content/browser/compositor/gpu_browser_compositor_output_surface.h

Index: content/browser/compositor/gpu_browser_compositor_output_surface.h
diff --git a/content/browser/compositor/gpu_browser_compositor_output_surface.h b/content/browser/compositor/gpu_browser_compositor_output_surface.h
index 5d2c7ed66e13d098b30595408c26f805c1ee4ba1..2720ae82c22f2c33ca90dde241ebe5f449cad406 100644
--- a/content/browser/compositor/gpu_browser_compositor_output_surface.h
+++ b/content/browser/compositor/gpu_browser_compositor_output_surface.h
@@ -55,9 +55,15 @@ class GpuBrowserCompositorOutputSurface
 #endif
 
   // cc::OutputSurface implementation.
-  void SwapBuffers(cc::CompositorFrame frame) override;
   bool BindToClient(cc::OutputSurfaceClient* client) override;
+  void EnsureBackbuffer() override;
+  void DiscardBackbuffer() override;
+  void BindFramebuffer() override;
+  void SwapBuffers(cc::CompositorFrame frame) override;
   uint32_t GetFramebufferCopyTextureFormat() override;
+  bool IsDisplayedAsOverlayPlane() const override;
+  unsigned GetOverlayTextureId() const override;
+  bool SurfaceIsSuspendForRecycle() const override;
 
   gpu::CommandBufferProxyImpl* GetCommandBufferProxy();