Stop using shell::GetInstance()->system_tray() in system tray items

ash/system/tray/tray_item_more.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_SYSTEM_TRAY_TRAY_ITEM_MORE_H_
 #define ASH_SYSTEM_TRAY_TRAY_ITEM_MORE_H_
 
 #include "ash/system/tray/tray_views.h"
 #include "ui/views/view.h"
 
 namespace views {
 class ImageView;
 class Label;
 class View;
 }
 
 namespace ash {
 
 class SystemTrayItem;
 
 namespace internal {
 
 // A view with a chevron ('>') on the right edge. Clicking on the view brings up
 // the detailed view of the tray-item that owns it.
 class TrayItemMore : public ActionableView {
  public:
   TrayItemMore(SystemTrayItem* owner, bool show_more);
   virtual ~TrayItemMore();
 
+  SystemTrayItem* owner() const { return owner_; }
+
   void SetLabel(const string16& label);
   void SetImage(const gfx::ImageSkia* image_skia);
   void SetAccessibleName(const string16& name);
 
  protected:
   // Replaces the default icon (on the left of the label), and allows a custom
   // view to be placed there. Once the default icon is replaced, |SetImage|
   // should never be called.
   void ReplaceIcon(views::View* view);
 
@@ skipping 13 matching lines @@
   views::ImageView* more_;
   string16 accessible_name_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayItemMore);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_ITEM_MORE_H_