MojoCompositorFrameSinkPrivate should support copy requests

content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h

Index: content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h
diff --git a/content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h b/content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h
index 0cdc3792fba1f11bcb39c84e24c5adb46a3dca46..a88e14dc88ca02fee50617f89d2cf8204cc02736 100644
--- a/content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h
+++ b/content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h
@@ -36,6 +36,12 @@ class OffscreenCanvasCompositorFrameSink
   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;