mash: Remove StatusAreaWidget references from system tray classes

ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.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_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_
 #define ASH_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_
 
 #include "ash/common/keyboard/keyboard_ui_observer.h"
 #include "ash/common/system/tray/tray_background_view.h"
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 
 namespace views {
 class ImageButton;
 }
 
 namespace ash {
-class StatusAreaWidget;
 
 // TODO(sky): make this visible on non-chromeos platforms.
 class VirtualKeyboardTray : public TrayBackgroundView,
                             public views::ButtonListener,
                             public KeyboardUIObserver {
  public:
-  explicit VirtualKeyboardTray(StatusAreaWidget* status_area_widget);
+  explicit VirtualKeyboardTray(WmShelf* wm_shelf);
   ~VirtualKeyboardTray() override;
 
   // TrayBackgroundView:
   void SetShelfAlignment(ShelfAlignment alignment) override;
   base::string16 GetAccessibleNameForTray() override;
   void HideBubbleWithView(const views::TrayBubbleView* bubble_view) override;
   void ClickedOutsideBubble() override;
   bool PerformAction(const ui::Event& event) override;
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // KeyboardUIObserver:
   void OnKeyboardEnabledStateChanged(bool new_value) override;
 
  private:
   views::ImageButton* button_;  // Not owned.
 
   DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_