Only send the FrameSinkId to client when it is necessary

services/ui/ws/test_change_tracker.h

Index: services/ui/ws/test_change_tracker.h
diff --git a/services/ui/ws/test_change_tracker.h b/services/ui/ws/test_change_tracker.h
index c4162ad02d2690a5e99032b0ef59184d3f48af0c..5ee6043562fa076cda8b1a9a1d6ea13f31a31fb9 100644
--- a/services/ui/ws/test_change_tracker.h
+++ b/services/ui/ws/test_change_tracker.h
@@ -144,8 +144,7 @@ class TestChangeTracker {
   // WindowTreeClient function.
   void OnEmbed(ClientSpecificId client_id,
                mojom::WindowDataPtr root,
-               bool drawn,
-               const cc::FrameSinkId& frame_sink_id);
+               bool drawn);
   void OnEmbeddedAppDisconnected(Id window_id);
   void OnUnembed(Id window_id);
   void OnCaptureChanged(Id new_capture_window_id, Id old_capture_window_id);
@@ -183,8 +182,7 @@ class TestChangeTracker {
   void OnChangeCompleted(uint32_t change_id, bool success);
   void OnTopLevelCreated(uint32_t change_id,
                          mojom::WindowDataPtr window_data,
-                         bool drawn,
-                         const cc::FrameSinkId& frame_sink_id);
+                         bool drawn);
   void OnWindowSurfaceChanged(Id window_id,
                               const cc::SurfaceInfo& surface_info);