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

ash/system/tray_update.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/tray_update.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray.h"
@@ skipping 146 matching lines @@
     : TrayImageItem(IDR_AURA_UBER_TRAY_UPDATE),
       severity_(UpdateObserver::UPDATE_NORMAL) {
 }
 
 TrayUpdate::~TrayUpdate() {}
 
 bool TrayUpdate::GetInitialVisibility() {
   return Shell::GetInstance()->tray_delegate()->SystemShouldUpgrade();
 }
 
-views::View* TrayUpdate::CreateDefaultView(user::LoginStatus status) {
+views::View* TrayUpdate::CreateDefaultView(user::LoginStatus status,
+                                           int bubble_width) {
   if (!Shell::GetInstance()->tray_delegate()->SystemShouldUpgrade())
     return NULL;
   return new UpdateView(severity_);
 }
 
 views::View* TrayUpdate::CreateDetailedView(user::LoginStatus status) {
-  return CreateDefaultView(status);
+  return CreateDefaultView(status, 0);
 }
 
 void TrayUpdate::DestroyDetailedView() {
   if (nagger_.get()) {
     // The nagger was being displayed. Now that the detailed view is being
     // closed, that means either the user clicks on it to restart, or the user
     // didn't click on it to restart. In either case, start the timer to show
     // the nag reminder again after the specified time.
     nagger_->RestartTimer();
   }
 }
 
 void TrayUpdate::OnUpdateRecommended(UpdateObserver::UpdateSeverity severity) {
   severity_ = severity;
   SetImageFromResourceId(DecideResource(severity_, false));
   tray_view()->SetVisible(true);
   if (!Shell::GetPrimaryRootWindowController()->shelf()->IsVisible() &&
       !nagger_.get()) {
     // The shelf is not visible, and there is no nagger scheduled.
     nagger_.reset(new tray::UpdateNagger(this));
   }
 }
 
 }  // namespace internal
 }  // namespace ash