mash: Break ash system tray dependencies on ash::ShelfWidget

ash/shelf/shelf_widget.h

 // Copyright (c) 2012 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_SHELF_WIDGET_H_
 #define ASH_SHELF_SHELF_WIDGET_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 12 matching lines @@
 class WmShelfAura;
 class WmWindow;
 class WorkspaceController;
 
 class ASH_EXPORT ShelfWidget : public views::Widget,
                                public views::WidgetObserver,
                                public ShelfLayoutManagerObserver {
  public:
   ShelfWidget(WmWindow* wm_shelf_container,
               WmWindow* wm_status_container,
+              WmShelfAura* wm_shelf_aura,
               WorkspaceController* workspace_controller);
   ~ShelfWidget() override;
 
   // Returns if shelf alignment option is enabled, and the user is able to
   // adjust the alignment (guest and supervised mode users cannot for example).
   static bool ShelfAlignmentAllowed();
 
   void OnShelfAlignmentChanged();
   ShelfAlignment GetAlignment() const;
 
@@ skipping 70 matching lines @@
   DelegateView* delegate_view_;
   BackgroundAnimator background_animator_;
   bool activating_as_fallback_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfWidget);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_WIDGET_H_