Eliminate ash::internal namespace

ash/system/tray/system_tray_bubble.cc

Index: ash/system/tray/system_tray_bubble.cc
diff --git a/ash/system/tray/system_tray_bubble.cc b/ash/system/tray/system_tray_bubble.cc
index 0316b54549d88172df7a35cf4d8c5e234bd1d22d..1aedaf0153bf99204f8a135fcf40ea844d17d137 100644
--- a/ash/system/tray/system_tray_bubble.cc
+++ b/ash/system/tray/system_tray_bubble.cc
@@ -127,8 +127,6 @@ class AnimationObserverDeleteLayer : public ui::ImplicitAnimationObserver {
 
 }  // namespace
 
-namespace internal {
-
 // SystemTrayBubble
 
 SystemTrayBubble::SystemTrayBubble(
@@ -384,5 +382,4 @@ void SystemTrayBubble::CreateItemViews(user::LoginStatus login_status) {
     focus_view->RequestFocus();
 }
 
-}  // namespace internal
 }  // namespace ash