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

ash/system/power/tray_power.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/power/tray_power.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/system/date/date_view.h"
 #include "ash/system/power/power_status_view.h"
@@ skipping 82 matching lines @@
   PowerSupplyStatus supply_status_;
 
   // Index of the current icon in the icon array image, or -1 if unknown.
   int battery_icon_index_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerTrayView);
 };
 
 class PowerNotificationView : public TrayNotificationView {
  public:
-  explicit PowerNotificationView(TrayPower* tray)
-      : TrayNotificationView(tray, 0),
+  explicit PowerNotificationView(TrayPower* owner)
+      : TrayNotificationView(owner, 0),
         battery_icon_index_(-1) {
     power_status_view_ =
         new PowerStatusView(PowerStatusView::VIEW_NOTIFICATION, true);
     InitView(power_status_view_);
   }
 
   void UpdatePowerStatus(const PowerSupplyStatus& status) {
     int index = TrayPower::GetBatteryImageIndex(status);
     if (battery_icon_index_ != index) {
       battery_icon_index_ = index;
@@ skipping 11 matching lines @@
   // Index of the current icon in the icon array image, or -1 if unknown.
   int battery_icon_index_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerNotificationView);
 };
 
 }  // namespace tray
 
 using tray::PowerNotificationView;
 
-TrayPower::TrayPower()
-    : power_tray_(NULL),
+TrayPower::TrayPower(SystemTray* system_tray)
+    : SystemTrayItem(system_tray),
+      power_tray_(NULL),
       notification_view_(NULL),
       notification_state_(NOTIFICATION_NONE) {
 }
 
 TrayPower::~TrayPower() {
 }
 
 // static
 int TrayPower::GetBatteryImageIndex(const PowerSupplyStatus& supply_status) {
   int image_index = 0;
@@ skipping 117 matching lines @@
       return false;
     case NOTIFICATION_CRITICAL:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace internal
 }  // namespace ash