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

ash/common/system/status_area_widget.h

Index: ash/common/system/status_area_widget.h
diff --git a/ash/system/status_area_widget.h b/ash/common/system/status_area_widget.h
similarity index 95%
rename from ash/system/status_area_widget.h
rename to ash/common/system/status_area_widget.h
index ce4eeb0fe8ad9edfff85fd35eb3d95ec420306a4..8fa40c4a11d0f143a652930f412f47cfa6a08e31 100644
--- a/ash/system/status_area_widget.h
+++ b/ash/common/system/status_area_widget.h
@@ -2,8 +2,8 @@
 // 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"
@@ -100,4 +100,4 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget {
 
 }  // namespace ash
 
-#endif  // ASH_SYSTEM_STATUS_AREA_WIDGET_H_
+#endif  // ASH_COMMON_SYSTEM_STATUS_AREA_WIDGET_H_