Eliminate ash::internal namespace

ash/drag_drop/drag_image_view.cc

Index: ash/drag_drop/drag_image_view.cc
diff --git a/ash/drag_drop/drag_image_view.cc b/ash/drag_drop/drag_image_view.cc
index 5beb81f850bf94eea052ab3db1983b1582064591..746d61960b973c18617575047977c618c1a8c461 100644
--- a/ash/drag_drop/drag_image_view.cc
+++ b/ash/drag_drop/drag_image_view.cc
@@ -15,8 +15,6 @@
 #include "ui/wm/core/shadow_types.h"
 
 namespace ash {
-namespace internal {
-
 namespace {
 using views::Widget;
 
@@ -171,5 +169,4 @@ void DragImageView::OnPaint(gfx::Canvas* canvas) {
   }
 }
 
-}  // namespace internal
 }  // namespace ash