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

ash/system/audio/tray_volume.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/audio/tray_volume.h"
 
 #include <cmath>
 
 #include "ash/ash_constants.h"
 #include "ash/shell.h"
@@ skipping 208 matching lines @@
       is_default_view_(false) {
 }
 
 TrayVolume::~TrayVolume() {
 }
 
 bool TrayVolume::GetInitialVisibility() {
   return IsAudioMuted();
 }
 
-views::View* TrayVolume::CreateDefaultView(user::LoginStatus status) {
+views::View* TrayVolume::CreateDefaultView(user::LoginStatus status,
+                                           int bubble_width) {
   volume_view_ = new tray::VolumeView;
   is_default_view_ = true;
   return volume_view_;
 }
 
 views::View* TrayVolume::CreateDetailedView(user::LoginStatus status) {
   volume_view_ = new tray::VolumeView;
   is_default_view_ = false;
   return volume_view_;
 }
@@ skipping 31 matching lines @@
       tray_view()->SetVisible(GetInitialVisibility());
 
   if (volume_view_)
     volume_view_->Update();
   else
     PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
 }
 
 }  // namespace internal
 }  // namespace ash