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

ash/system/date/tray_date.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/date/tray_date.h"
 
 #include "ash/shell.h"
 #include "ash/system/date/date_view.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ skipping 106 matching lines @@
   ash::internal::TrayPopupHeaderButton* lock_;
 
   DISALLOW_COPY_AND_ASSIGN(DateDefaultView);
 };
 
 }  // namespace
 
 namespace ash {
 namespace internal {
 
-TrayDate::TrayDate()
-    : time_tray_(NULL) {
+TrayDate::TrayDate(SystemTray* system_tray)
+    : SystemTrayItem(system_tray),
+      time_tray_(NULL) {
 }
 
 TrayDate::~TrayDate() {
 }
 
 views::View* TrayDate::CreateTrayView(user::LoginStatus status) {
   CHECK(time_tray_ == NULL);
   ClockLayout clock_layout =
-      ash::Shell::GetInstance()->system_tray()->shelf_alignment() ==
-         SHELF_ALIGNMENT_BOTTOM ?
-      HORIZONTAL_CLOCK : VERTICAL_CLOCK;
+      system_tray()->shelf_alignment() == SHELF_ALIGNMENT_BOTTOM ?
+          HORIZONTAL_CLOCK : VERTICAL_CLOCK;
   time_tray_ = new tray::TimeView(clock_layout);
-  views::View* view = new TrayItemView;
+  views::View* view = new TrayItemView(this);
   view->AddChildView(time_tray_);
   return view;
 }
 
 views::View* TrayDate::CreateDefaultView(user::LoginStatus status) {
   return new DateDefaultView(status);
 }
 
 views::View* TrayDate::CreateDetailedView(user::LoginStatus status) {
   return NULL;
@@ skipping 25 matching lines @@
     time_tray_->UpdateTimeFormat();
 }
 
 void TrayDate::Refresh() {
   if (time_tray_)
     time_tray_->UpdateText();
 }
 
 }  // namespace internal
 }  // namespace ash