chromeos: Makes mushrome use simplified display management

ash/mus/bridge/shell_port_mash.h

 // Copyright 2016 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_BRIDGE_SHELL_PORT_MASH_H_
 #define ASH_MUS_BRIDGE_SHELL_PORT_MASH_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 122 matching lines @@
     MusSpecificState();
     ~MusSpecificState();
 
     std::unique_ptr<PointerWatcherAdapter> pointer_watcher_adapter;
     std::unique_ptr<AcceleratorControllerDelegateAura>
         accelerator_controller_delegate;
   };
 
   WindowManager* window_manager_;
 
+  // TODO(sky): remove this once mash supports simple display management.
   WmWindow* primary_root_window_;
 
   // Only one of |mash_state_| or |mus_state_| is created, depending upon
   // Config.
   std::unique_ptr<MashSpecificState> mash_state_;
   std::unique_ptr<MusSpecificState> mus_state_;
 
   std::unique_ptr<SessionStateDelegate> session_state_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellPortMash);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_BRIDGE_SHELL_PORT_MASH_H_