Fixes bug in ServerWindowCompositorFrameSinkManager

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 a2972d6ef84be5f07049b63bed5b92024b4daec7..965e47110b50d06d9e01a0698c3626c6b231c534 100644
--- a/services/ui/ws/server_window_compositor_frame_sink_manager.h
+++ b/services/ui/ws/server_window_compositor_frame_sink_manager.h
@@ -33,6 +33,7 @@ struct CompositorFrameSinkData {
   cc::mojom::MojoCompositorFrameSinkPrivatePtr compositor_frame_sink;
   cc::mojom::MojoCompositorFrameSinkPrivateRequest
       pending_compositor_frame_sink_request;
+  cc::FrameSinkId frame_sink_id;
 };
 
 // ServerWindowCompositorFrameSinkManager tracks the surfaces associated with a
@@ -83,6 +84,8 @@ class ServerWindowCompositorFrameSinkManager {
                             const cc::SurfaceId& surface_id,
                             const gfx::Size& frame_size);
 
+  void OnRootChanged(ServerWindow* old_root, ServerWindow* new_root);
+
  private:
   friend class ServerWindowCompositorFrameSinkManagerTestApi;
   friend class ServerWindowCompositorFrameSink;