Eliminate ash::internal namespace

ash/system/tray/hover_highlight_view.cc

Index: ash/system/tray/hover_highlight_view.cc
diff --git a/ash/system/tray/hover_highlight_view.cc b/ash/system/tray/hover_highlight_view.cc
index e78944cc9a56074a8f177bc1dffaf72124ca7aed..ac445b6b2189f174c2b6154ad0a74800ec436a66 100644
--- a/ash/system/tray/hover_highlight_view.cc
+++ b/ash/system/tray/hover_highlight_view.cc
@@ -25,7 +25,6 @@ const int kCheckLabelPadding = 4;
 }  // namespace
 
 namespace ash {
-namespace internal {
 
 HoverHighlightView::HoverHighlightView(ViewClickListener* listener)
     : listener_(listener),
@@ -186,5 +185,4 @@ void HoverHighlightView::OnFocus() {
   ActionableView::OnFocus();
 }
 
-}  // namespace internal
 }  // namespace ash