MojoCompositorFrameSinkPrivate should support copy requests

cc/surfaces/compositor_frame_sink_support.h

Index: cc/surfaces/compositor_frame_sink_support.h
diff --git a/cc/surfaces/compositor_frame_sink_support.h b/cc/surfaces/compositor_frame_sink_support.h
index 8471bbd15c6b186b1c4678f6f64a7246ab41fd18..d2fa5d6d83d0f92c625e08eccf3da6d425345b0e 100644
--- a/cc/surfaces/compositor_frame_sink_support.h
+++ b/cc/surfaces/compositor_frame_sink_support.h
@@ -8,6 +8,8 @@
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/output/compositor_frame.h"
+#include "cc/output/copy_output_request.h"
+#include "cc/output/copy_output_result.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/display.h"
 #include "cc/surfaces/display_client.h"
@@ -46,12 +48,19 @@ class CC_SURFACES_EXPORT CompositorFrameSinkSupport
   void Satisfy(const SurfaceSequence& sequence);
   void AddChildFrameSink(const FrameSinkId& child_frame_sink_id);
   void RemoveChildFrameSink(const FrameSinkId& child_frame_sink_id);
+  void RequestCopyOfSurface(std::unique_ptr<CopyOutputRequest> request);
+  void ReleaseCopyOfSurface(const gpu::Mailbox& mailbox,
+                            const gpu::SyncToken& sync_token,
+                            bool is_lost);
 
   Display* display() { return display_.get(); }
 
  private:
   void DidReceiveCompositorFrameAck();
 
+  void OnTextureReceived(CopyOutputRequest::CopyOutputRequestCallback callback,
+                         std::unique_ptr<CopyOutputResult> result);
+
   // DisplayClient implementation.
   void DisplayOutputSurfaceLost() override;
   void DisplayWillDrawAndSwap(bool will_draw_and_swap,
@@ -104,6 +113,9 @@ class CC_SURFACES_EXPORT CompositorFrameSinkSupport
   // The set of BeginFrame children of this CompositorFrameSink.
   std::unordered_set<FrameSinkId, FrameSinkIdHash> child_frame_sinks_;
 
+  std::map<gpu::Mailbox, std::unique_ptr<SingleReleaseCallback>>
+      release_callbacks_;
+
   base::WeakPtrFactory<CompositorFrameSinkSupport> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorFrameSinkSupport);