Move common notification layout to base class

ash/system/locale/tray_locale.h

Index: ash/system/locale/tray_locale.h
diff --git a/ash/system/locale/tray_locale.h b/ash/system/locale/tray_locale.h
index c0d114cc30ddfd09d9ba1b8f7b4ca1bdbd098ff6..d716035f5f1dc1785d2e8070b493be0d73f365ac 100644
--- a/ash/system/locale/tray_locale.h
+++ b/ash/system/locale/tray_locale.h
@@ -9,7 +9,7 @@
 #include <string>
 
 #include "ash/system/locale/locale_observer.h"
-#include "ash/system/tray/tray_image_item.h"
+#include "ash/system/tray/system_tray_item.h"
 
 namespace ash {
 namespace internal {
@@ -18,7 +18,7 @@ namespace tray {
 class LocaleNotificationView;
 }
 
-class TrayLocale : public TrayImageItem,
+class TrayLocale : public SystemTrayItem,
                    public LocaleObserver {
  public:
   TrayLocale();