Move ash::DisplayManager switches to ui::display

ash/display/screen_ash.cc

 // 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.
 
 #include "ash/display/screen_ash.h"
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shelf/shelf_widget.h"
 #include "ash/common/wm/root_window_finder.h"
 #include "ash/display/display_manager.h"
@@ skipping 172 matching lines @@
   // If there is no native, or the native was for shutdown,
   // use ash's screen.
   if (!current || current == screen_for_shutdown)
     display::Screen::SetScreenInstance(screen.get());
   return new DisplayManager(std::move(screen));
 }
 
 // static
 void ScreenAsh::CreateScreenForShutdown() {
   delete screen_for_shutdown;
-  // fix this up...
   screen_for_shutdown = new ScreenForShutdown(display::Screen::GetScreen());
   display::Screen::SetScreenInstance(screen_for_shutdown);
 }
 
 }  // namespace ash