Eliminate ash::internal namespace

ash/wm/maximize_mode/workspace_backdrop_delegate.h

 // Copyright 2014 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.
 
 #ifndef ASH_WM_MAXIMIZE_MODE_WORKSPACE_BACKDROP_DELEGATE_H_
 #define ASH_WM_MAXIMIZE_MODE_WORKSPACE_BACKDROP_DELEGATE_H_
 
 #include "ash/wm/workspace/workspace_layout_manager_delegate.h"
 #include "ui/aura/window_observer.h"
 
 namespace aura {
 class Window;
 }
 
 namespace ui {
 class Layer;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace ash {
 
-namespace internal {
-
 // A background which gets created for a container |window| and which gets
 // stacked behind the topmost window (within that container) covering the
 // entire container.
 class WorkspaceBackdropDelegate : public aura::WindowObserver,
                                   public WorkspaceLayoutManagerDelegate {
  public:
   explicit WorkspaceBackdropDelegate(aura::Window* container);
   virtual ~WorkspaceBackdropDelegate();
 
   // WindowObserver overrides:
@@ skipping 29 matching lines @@
 
   // The window which is being "maximized".
   aura::Window* container_;
 
   // If true, the |RestackOrHideWindow| might recurse.
   bool in_restacking_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceBackdropDelegate);
 };
 
-}  // namespace internal
-
 }  // namespace ash
 
 #endif  // ASH_WM_MAXIMIZE_MODE_WORKSPACE_BACKDROP_DELEGATE_H_