Moves ShellObserver to ash/common

ash/display/projecting_observer_chromeos.h

 // 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.
 
 #ifndef ASH_DISPLAY_PROJECTING_OBSERVER_CHROMEOS_H_
 #define ASH_DISPLAY_PROJECTING_OBSERVER_CHROMEOS_H_
 
 #include "ash/ash_export.h"
-#include "ash/shell_observer.h"
+#include "ash/common/shell_observer.h"
 #include "base/macros.h"
 #include "ui/display/chromeos/display_configurator.h"
 
 namespace chromeos {
 class PowerManagerClient;
 }
 
 namespace ash {
 
 class ASH_EXPORT ProjectingObserver : public ui::DisplayConfigurator::Observer,
@@ skipping 27 matching lines @@
 
   // Weak pointer to the DBusClient PowerManagerClient;
   chromeos::PowerManagerClient* power_manager_client_;
 
   DISALLOW_COPY_AND_ASSIGN(ProjectingObserver);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_PROJECTING_OBSERVER_CHROMEOS_H_