WIP: Propagate SurfaceID up window tree hierarchy

services/ui/ws/server_window_delegate.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_SERVER_WINDOW_DELEGATE_H_
 #define SERVICES_UI_WS_SERVER_WINDOW_DELEGATE_H_
 
 #include <memory>
 
 #include "services/ui/public/interfaces/mus_constants.mojom.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 
 namespace ui {
 
-class SurfacesState;
+namespace surfaces {
+class DisplayCompositor;
+}
 
 namespace ws {
 
 struct ClientWindowId;
 class ServerWindow;
 struct WindowId;
 
 class ServerWindowDelegate {
  public:
-  virtual SurfacesState* GetSurfacesState() = 0;
+  virtual surfaces::DisplayCompositor* GetDisplayCompositor() = 0;
 
   virtual void OnScheduleWindowPaint(ServerWindow* window) = 0;
 
   // Returns the root of the window tree to which this |window| is attached.
   // Returns null if this window is not attached up through to a root window.
   virtual const ServerWindow* GetRootWindow(
       const ServerWindow* window) const = 0;
 
   // Schedules a callback to DestroySurfacesScheduledForDestruction() at the
   // appropriate time, which may be synchronously.
   virtual void ScheduleSurfaceDestruction(ServerWindow* window) = 0;
 
  protected:
   virtual ~ServerWindowDelegate() {}
 };
 
 }  // namespace ws
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_SERVER_WINDOW_DELEGATE_H_