Move PlatformDisplayDefault into it's own file.

services/ui/ws/display.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 SERVICES_UI_WS_DISPLAY_H_
 #define SERVICES_UI_WS_DISPLAY_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <queue>
 #include <set>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "services/ui/common/types.h"
 #include "services/ui/public/interfaces/window_manager_constants.mojom.h"
 #include "services/ui/public/interfaces/window_tree_host.mojom.h"
 #include "services/ui/ws/focus_controller_delegate.h"
 #include "services/ui/ws/focus_controller_observer.h"
 #include "services/ui/ws/platform_display.h"
+#include "services/ui/ws/platform_display_delegate.h"
 #include "services/ui/ws/server_window.h"
 #include "services/ui/ws/server_window_observer.h"
 #include "services/ui/ws/server_window_tracker.h"
 #include "services/ui/ws/user_id_tracker_observer.h"
 #include "services/ui/ws/window_manager_window_tree_factory_set_observer.h"
 #include "ui/display/display.h"
 
 namespace ui {
 namespace ws {
 
@@ skipping 166 matching lines @@
 
   WindowManagerDisplayRootMap window_manager_display_root_map_;
 
   DISALLOW_COPY_AND_ASSIGN(Display);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_DISPLAY_H_