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

ash/system/brightness/tray_brightness.cc

 // 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.
 
 #include "ash/system/brightness/tray_brightness.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/ash_constants.h"
 #include "ash/shell.h"
 #include "ash/system/brightness/brightness_control_delegate.h"
@@ skipping 143 matching lines @@
 
 void TrayBrightness::HandleInitialBrightness(double percent) {
   if (!got_current_percent_)
     OnBrightnessChanged(percent, false);
 }
 
 views::View* TrayBrightness::CreateTrayView(user::LoginStatus status) {
   return NULL;
 }
 
-views::View* TrayBrightness::CreateDefaultView(user::LoginStatus status) {
+views::View* TrayBrightness::CreateDefaultView(user::LoginStatus status,
+                                               int bubble_width) {
   return NULL;
 }
 
 views::View* TrayBrightness::CreateDetailedView(user::LoginStatus status) {
   CHECK(brightness_view_ == NULL);
   brightness_view_ = new tray::BrightnessView(current_percent_);
   is_default_view_ = false;
   return brightness_view_;
 }
 
@@ skipping 27 matching lines @@
     return;
 
   if (brightness_view_)
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
   else
     PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
 }
 
 }  // namespace internal
 }  // namespace ash