MojoCompositorFrameSinkPrivate should support copy requests

components/exo/compositor_frame_sink.h

Index: components/exo/compositor_frame_sink.h
diff --git a/components/exo/compositor_frame_sink.h b/components/exo/compositor_frame_sink.h
index da24d178f11249fa1303a1250782afa8f0aa01f0..04c3357d9117727a10c04c4546cfb4d694fede98 100644
--- a/components/exo/compositor_frame_sink.h
+++ b/components/exo/compositor_frame_sink.h
@@ -33,6 +33,12 @@ class CompositorFrameSink : public cc::CompositorFrameSinkSupportClient,
   void Require(const cc::LocalSurfaceId& local_surface_id,
                const cc::SurfaceSequence& sequence) override;
   void Satisfy(const cc::SurfaceSequence& sequence) override;
+  void RequestCopyOfSurface(
+      std::unique_ptr<cc::CopyOutputRequest> request,
+      const RequestCopyOfSurfaceCallback& callback) override;
+  void DeleteMailbox(const gpu::Mailbox& mailbox,
+                     const ::gpu::SyncToken& sync_token,
+                     bool is_lost) override;
 
   // Overridden from cc::CompositorFrameSinkSupportClient:
   void DidReceiveCompositorFrameAck() override;