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

ash/system/brightness/tray_brightness.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_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 #define ASH_SYSTEM_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 
 #include "ash/system/brightness/brightness_observer.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "base/compiler_specific.h"
@@ skipping 17 matching lines @@
   // can be initialized.
   void GetInitialBrightness();
 
   // Updates |current_percent_| with the initial brightness requested by
   // GetInitialBrightness(), if we haven't seen the brightness already in the
   // meantime.
   void HandleInitialBrightness(double percent);
 
   // Overridden from SystemTrayItem.
   virtual views::View* CreateTrayView(user::LoginStatus status) OVERRIDE;
-  virtual views::View* CreateDefaultView(user::LoginStatus status) OVERRIDE;
+  virtual views::View* CreateDefaultView(user::LoginStatus status,
+                                         int bubble_width) OVERRIDE;
   virtual views::View* CreateDetailedView(user::LoginStatus status) OVERRIDE;
   virtual void DestroyTrayView() OVERRIDE;
   virtual void DestroyDefaultView() OVERRIDE;
   virtual void DestroyDetailedView() OVERRIDE;
   virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) OVERRIDE;
   virtual bool ShouldShowLauncher() const OVERRIDE;
 
   // Overridden from BrightnessObserver.
   virtual void OnBrightnessChanged(double percent,
                                    bool user_initiated) OVERRIDE;
@@ skipping 14 matching lines @@
   // Has |current_percent_| been initialized?
   bool got_current_percent_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBrightness);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_BRIGHTNESS_TRAY_BRIGHTNESS_H_