mash: Move StatusTray and StatusAreaWidget to //ash/common

ash/common/system/status_area_widget.h

 // Copyright (c) 2012 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_SYSTEM_STATUS_AREA_WIDGET_H_
-#define ASH_SYSTEM_STATUS_AREA_WIDGET_H_
+#ifndef ASH_COMMON_SYSTEM_STATUS_AREA_WIDGET_H_
+#define ASH_COMMON_SYSTEM_STATUS_AREA_WIDGET_H_
 
 #include "ash/ash_export.h"
 #include "ash/common/login_status.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "base/macros.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 class OverviewButtonTray;
 class ShellDelegate;
@@ skipping 76 matching lines @@
 #endif
   LoginStatus login_status_;
 
   WmShelf* wm_shelf_;
 
   DISALLOW_COPY_AND_ASSIGN(StatusAreaWidget);
 };
 
 }  // namespace ash
 
-#endif  // ASH_SYSTEM_STATUS_AREA_WIDGET_H_
+#endif  // ASH_COMMON_SYSTEM_STATUS_AREA_WIDGET_H_