Only send the FrameSinkId to client when it is necessary

services/ui/ws/test_change_tracker.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SERVICES_UI_WS_TEST_CHANGE_TRACKER_H_
 #define SERVICES_UI_WS_TEST_CHANGE_TRACKER_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 126 matching lines @@
   ~TestChangeTracker();
 
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
 
   std::vector<Change>* changes() { return &changes_; }
 
   // Each of these functions generate a Change. There is one per
   // 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);
   void OnFrameSinkIdAllocated(Id window_id,
                               const cc::FrameSinkId& frame_sink_id);
   void OnTransientWindowAdded(Id window_id, Id transient_window_id);
   void OnTransientWindowRemoved(Id window_id, Id transient_window_id);
   void OnWindowBoundsChanged(
       Id window_id,
       const gfx::Rect& old_bounds,
@@ skipping 17 matching lines @@
                               uint32_t window_id);
   void OnWindowSharedPropertyChanged(
       Id window_id,
       const std::string& name,
       const base::Optional<std::vector<uint8_t>>& data);
   void OnWindowFocused(Id window_id);
   void OnWindowCursorChanged(Id window_id, const ui::CursorData& cursor);
   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);
 
  private:
   void AddChange(const Change& change);
 
   Delegate* delegate_;
   std::vector<Change> changes_;
 
   DISALLOW_COPY_AND_ASSIGN(TestChangeTracker);
 };
 
 }  // namespace ws
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_TEST_CHANGE_TRACKER_H_