mash: remove more shell/shelf WmWindow usage.

ash/shelf/wm_shelf.h

 // Copyright 2016 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_SHELF_WM_SHELF_H_
 #define ASH_SHELF_WM_SHELF_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/public/cpp/shelf_types.h"
 #include "ash/shelf/shelf_layout_manager_observer.h"
 #include "base/observer_list.h"
 
+namespace aura {
+class Window;
+}
+
 namespace gfx {
 class Rect;
 }
 
 namespace ui {
 class GestureEvent;
 }
 
 namespace ash {
 
@@ skipping 10 matching lines @@
 
 // Controller for the shelf state. Exists for the lifetime of each root window
 // controller. Note that the shelf widget may not be created until after login.
 class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
  public:
   WmShelf();
   ~WmShelf() override;
 
   // Returns the shelf for the display that |window| is on. Note that the shelf
   // widget may not exist, or the shelf may not be visible.
-  static WmShelf* ForWindow(WmWindow* window);
+  static WmShelf* ForWindow(aura::Window* window);
 
   // Returns if shelf alignment options are enabled, and the user is able to
   // adjust the alignment (eg. not allowed in guest and supervised user modes).
   static bool CanChangeShelfAlignment();
 
   void CreateShelfWidget(WmWindow* root);
   void ShutdownShelfWidget();
   void DestroyShelfWidget();
 
   ShelfLayoutManager* shelf_layout_manager() const {
@@ skipping 123 matching lines @@
   // Forwards touch gestures on a bezel sensor to the shelf.
   // TODO(mash): Facilitate simliar functionality in mash: crbug.com/636647
   std::unique_ptr<ShelfBezelEventHandler> bezel_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(WmShelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_WM_SHELF_H_