Eliminate ash::internal namespace

ash/system/tray/tray_notification_view.cc

Index: ash/system/tray/tray_notification_view.cc
diff --git a/ash/system/tray/tray_notification_view.cc b/ash/system/tray/tray_notification_view.cc
index c09589285eadea8d922df6a3aa223dc178e3fba0..d27296f814c89e9d9a7e98dbbfd25867e66f37b4 100644
--- a/ash/system/tray/tray_notification_view.cc
+++ b/ash/system/tray/tray_notification_view.cc
@@ -16,7 +16,6 @@
 #include "ui/views/layout/grid_layout.h"
 
 namespace ash {
-namespace internal {
 
 TrayNotificationView::TrayNotificationView(SystemTrayItem* owner, int icon_id)
     : owner_(owner),
@@ -168,5 +167,4 @@ void TrayNotificationView::HandleClickAction() {
   OnClickAction();
 }
 
-}  // namespace internal
 }  // namespace ash