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 f45782acee3a9001d600cc4f581efafe27679c4a..e1da184e6bde555f115ad1207d2906f85e122eeb 100644
--- a/services/ui/ws/server_window_compositor_frame_sink_manager.h
+++ b/services/ui/ws/server_window_compositor_frame_sink_manager.h
@@ -62,13 +62,19 @@ class ServerWindowCompositorFrameSinkManager {
   void AddChildFrameSinkId(const cc::FrameSinkId& frame_sink_id);
   void RemoveChildFrameSinkId(const cc::FrameSinkId& frame_sink_id);
 
+  // Claims this FrameSinkId will embed |surface_id| so it should own the
+  // temporary reference to |surface_id|.
+  void ClaimTemporaryReference(const cc::SurfaceId& surface_id);
+
   void OnRootChanged(ServerWindow* old_root, ServerWindow* new_root);
 
  private:
   friend class ServerWindowCompositorFrameSinkManagerTestApi;
   friend class ServerWindowCompositorFrameSink;
 
-  ServerWindow* window_;
+  void CreateCompositorFrameSinkData();
+
+  ServerWindow* const window_;
 
   std::unique_ptr<CompositorFrameSinkData> frame_sink_data_;