Makes WorkspaceLayoutManager use ash/wm/common types

ash/wm/common/switchable_windows.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_SWITCHABLE_WINDOWS_H_
-#define ASH_SWITCHABLE_WINDOWS_H_
+#ifndef ASH_WM_COMMON_SWITCHABLE_WINDOWS_H_
+#define ASH_WM_COMMON_SWITCHABLE_WINDOWS_H_
 
 #include <stddef.h>
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
 
-namespace aura {
-  class Window;
-}
+namespace ash {
+namespace wm {
 
-namespace ash {
+class WmWindow;
 
 // List of containers which contain windows that can be switched via Alt+Tab to.
 ASH_EXPORT extern const int kSwitchableWindowContainerIds[];
 
 // The number of elements in kSwitchableWindowContainerIds.
 ASH_EXPORT extern const size_t kSwitchableWindowContainerIdsLength;
 
 // Returns true if |window| is a container for windows which can be switched to.
-ASH_EXPORT bool IsSwitchableContainer(const aura::Window* window);
+ASH_EXPORT bool IsSwitchableContainer(const WmWindow* window);
 
+}  // namespace wm
 }  // namespace ash
 
-#endif  // ASH_SWITCHABLE_WINDOWS_H_
+#endif  // ASH_WM_COMMON_SWITCHABLE_WINDOWS_H_