Draw the offscreen texture to reflector's surface without extra copy

content/browser/compositor/browser_compositor_output_surface.h

Index: content/browser/compositor/browser_compositor_output_surface.h
diff --git a/content/browser/compositor/browser_compositor_output_surface.h b/content/browser/compositor/browser_compositor_output_surface.h
index 615a54e30c5ab928021fa3017529fdaf413ff82e..1265f632b7d33c93fa20f63283342678ff2dce08 100644
--- a/content/browser/compositor/browser_compositor_output_surface.h
+++ b/content/browser/compositor/browser_compositor_output_surface.h
@@ -19,6 +19,7 @@ class BrowserCompositorOverlayCandidateValidator;
 class ContextProviderCommandBuffer;
 class ReflectorImpl;
 class WebGraphicsContext3DCommandBufferImpl;
+class OwnedMailbox;
 
 class CONTENT_EXPORT BrowserCompositorOutputSurface
     : public cc::OutputSurface,
@@ -39,6 +40,15 @@ class CONTENT_EXPORT BrowserCompositorOutputSurface
 
   void SetReflector(ReflectorImpl* reflector);
 
+  // Returns a mailbox that holds the texture used for offscreen
+  // output surface. nullptr if the output surface isn't offscreen
+  // surface.
+  virtual scoped_refptr<OwnedMailbox> GetTextureMailbox();
+
+  // Returns a callback that will be called when all mirroring
+  // compositors have started composition.
+  virtual base::Closure CreateCompositionStartedCallback();
+
 #if defined(OS_MACOSX)
   virtual void OnSurfaceDisplayed() = 0;
   virtual void SetSurfaceSuspendedForRecycle(bool suspended) = 0;