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 84 matching lines @@
 namespace ash {
 namespace internal {
 
 namespace tray {
 
 class UpdateNagger : public ui::LayerAnimationObserver {
  public:
   explicit UpdateNagger(SystemTrayItem* owner)
       : owner_(owner) {
     RestartTimer();
-    Shell::GetInstance()->system_tray()->GetWidget()->GetNativeView()->layer()->
+    owner_->system_tray()->GetWidget()->GetNativeView()->layer()->
         GetAnimator()->AddObserver(this);
   }
 
   virtual ~UpdateNagger() {
     internal::StatusAreaWidget* status_area =
         ash::Shell::GetInstance()->status_area_widget();
     if (status_area) {
       status_area->system_tray()->GetWidget()->GetNativeView()->layer()->
           GetAnimator()->RemoveObserver(this);
     }
@@ skipping 30 matching lines @@
       ui::LayerAnimationSequence* sequence) OVERRIDE {}
 
   SystemTrayItem* owner_;
   base::OneShotTimer<UpdateNagger> timer_;
 
   DISALLOW_COPY_AND_ASSIGN(UpdateNagger);
 };
 
 }  // namespace tray
 
-TrayUpdate::TrayUpdate()
-    : TrayImageItem(IDR_AURA_UBER_TRAY_UPDATE),
+TrayUpdate::TrayUpdate(SystemTray* system_tray)
+    : TrayImageItem(system_tray, 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) {
@@ skipping 22 matching lines @@
   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