Eliminate ash::internal namespace

ash/drag_drop/drag_image_view.h

Index: ash/drag_drop/drag_image_view.h
diff --git a/ash/drag_drop/drag_image_view.h b/ash/drag_drop/drag_image_view.h
index 04578477e95b3f5e258a83f97827dd315280d23d..fd5382e5c1c39e6897aa7ec75bd8c16fee883be1 100644
--- a/ash/drag_drop/drag_image_view.h
+++ b/ash/drag_drop/drag_image_view.h
@@ -13,7 +13,6 @@ class Widget;
 }
 
 namespace ash {
-namespace internal {
 
 // This class allows to show a (native) view always on top of everything. It
 // does this by creating a widget and setting the content as the given view. The
@@ -72,7 +71,6 @@ class DragImageView : public views::ImageView {
   DISALLOW_COPY_AND_ASSIGN(DragImageView);
 };
 
-}  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_DRAG_DROP_DRAG_IMAGE_VIEW_H_