Rename the aura_shell namespace to ash

ash/drag_drop/drag_image_view.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/drag_drop/drag_image_view.h"
 
 #include "ui/views/widget/widget.h"
 
-namespace aura_shell {
+namespace ash {
 namespace internal {
 
 namespace {
 using views::Widget;
 
 Widget* CreateDragWidget() {
   Widget* drag_widget = new Widget;
   Widget::InitParams params;
   params.type = Widget::InitParams::TYPE_TOOLTIP;
   params.keep_on_top = true;
@@ skipping 30 matching lines @@
 void DragImageView::SetWidgetVisible(bool visible) {
   if (visible != widget_->IsVisible()) {
     if (visible)
       widget_->Show();
     else
       widget_->Hide();
   }
 }
 
 }  // namespace internal
-}  // namespace aura_shell
+}  // namespace ash