chromeos: Move files in //ash/common to //ash

ash/display/shutdown_observer_chromeos.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_DISPLAY_SHUTDOWN_OBSERVER_CHROMEOS_H_
 #define ASH_DISPLAY_SHUTDOWN_OBSERVER_CHROMEOS_H_
 
-#include "ash/common/shell_observer.h"
+#include "ash/shell_observer.h"
 #include "base/macros.h"
 
 namespace display {
 class DisplayConfigurator;
 }
 
 namespace ash {
 
 // Adds self as ShellObserver and listens for OnAppTerminating() on behalf of
 // |display_configurator_|.
 class ShutdownObserver : public ShellObserver {
  public:
   explicit ShutdownObserver(display::DisplayConfigurator* display_configurator);
   ~ShutdownObserver() override;
 
  private:
   // ShellObserver:
   void OnAppTerminating() override;
 
   display::DisplayConfigurator* display_configurator_;
 
   DISALLOW_COPY_AND_ASSIGN(ShutdownObserver);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_SHUTDOWN_OBSERVER_CHROMEOS_H_