Implement temporary reference assignment with DisplayCompositor.

services/ui/ws/server_window_compositor_frame_sink_manager.h

Index: services/ui/ws/server_window_compositor_frame_sink_manager.h
diff --git a/services/ui/ws/server_window_compositor_frame_sink_manager.h b/services/ui/ws/server_window_compositor_frame_sink_manager.h
index fa27bc1011d6abdd8658eb47be22f93c4906fe0b..fbd5483e97569c7909baf4fb170ea29d1ab9a81b 100644
--- a/services/ui/ws/server_window_compositor_frame_sink_manager.h
+++ b/services/ui/ws/server_window_compositor_frame_sink_manager.h
@@ -37,6 +37,10 @@ class ServerWindowCompositorFrameSinkManager {
       cc::mojom::MojoCompositorFrameSinkRequest request,
       cc::mojom::MojoCompositorFrameSinkClientPtr client);
 
+  // Claims this FrameSinkId will embed |surface_id| so it should own the
+  // temporary reference to |surface_id|.
+  void ClaimTemporaryReference(const cc::SurfaceId& surface_id);
+
  private:
   ServerWindow* const window_;
   cc::mojom::MojoCompositorFrameSinkPrivatePtr compositor_frame_sink_;