[cc] Mailbox Output Surface Support

cc/output_surface.h

Index: cc/output_surface.h
diff --git a/cc/output_surface.h b/cc/output_surface.h
index de075e2b7dff79ae1b65b3028b8dfd1533147e28..0b02e50abfa432e6b192162cef67e907430e00f3 100644
--- a/cc/output_surface.h
+++ b/cc/output_surface.h
@@ -13,6 +13,11 @@
 #include "third_party/WebKit/Source/Platform/chromium/public/WebCompositorOutputSurface.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
 
+namespace gfx {
+class Rect;
+class Size;
+}
+
 namespace cc {
 
 class CompositorFrame;
@@ -70,6 +75,16 @@ class CC_EXPORT OutputSurface : public WebKit::WebCompositorOutputSurface {
   // steal the contents of the CompositorFrame passed in.
   virtual void SendFrameToParentCompositor(CompositorFrame*);
 
+  virtual void EnsureBackbuffer();
+  virtual void DiscardBackbuffer();
+
+  virtual void Reshape(gfx::Size size);
+
+  virtual void BindFramebuffer();
+
+  virtual void PostSubBuffer(gfx::Rect rect);
+  virtual void SwapBuffers();
+
   // Notifies frame-rate smoothness preference. If true, all non-critical
   // processing should be stopped, or lowered in priority.
   virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}
@@ -79,6 +94,7 @@ class CC_EXPORT OutputSurface : public WebKit::WebCompositorOutputSurface {
   struct cc::OutputSurface::Capabilities capabilities_;
   scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
   scoped_ptr<cc::SoftwareOutputDevice> software_device_;
+  bool has_gl_discard_backbuffer_;
 };
 
 }  // namespace cc