Move DisplayList to display; add ScreenBase.

ash/mus/window_manager.h

 // Copyright 2015 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 ASH_MUS_WINDOW_MANAGER_H_
 #define ASH_MUS_WINDOW_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <set>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "services/ui/common/types.h"
 #include "services/ui/public/cpp/window_manager_delegate.h"
 #include "services/ui/public/cpp/window_observer.h"
 #include "services/ui/public/cpp/window_tree_client_delegate.h"
 #include "services/ui/public/interfaces/window_manager.mojom.h"
 
 namespace display {
 class Display;
-class Screen;
+class ScreenBase;
 }
 
 namespace shell {
 class Connector;
 }
 
 namespace views {
 class PointerWatcherEventRouter;
 }
 
@@ skipping 100 matching lines @@
 
   std::unique_ptr<views::PointerWatcherEventRouter>
       pointer_watcher_event_router_;
 
   std::unique_ptr<ShadowController> shadow_controller_;
 
   std::set<std::unique_ptr<RootWindowController>> root_window_controllers_;
 
   base::ObserverList<WindowManagerObserver> observers_;
 
-  std::unique_ptr<display::Screen> screen_;
+  std::unique_ptr<display::ScreenBase> screen_;
 
   std::unique_ptr<WmShellMus> shell_;
 
   std::unique_ptr<WmLookupMus> lookup_;
 
   std::map<uint16_t, AcceleratorHandler*> accelerator_handlers_;
   uint16_t next_accelerator_namespace_id_ = 0u;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManager);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_WINDOW_MANAGER_H_