Prepare SystemTray to support notifications

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 "ash/shell.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_views.h"
@@ skipping 141 matching lines @@
   VolumeButton* icon_;
   views::Slider* slider_;
 
   DISALLOW_COPY_AND_ASSIGN(VolumeView);
 };
 
 }  // namespace tray
 
 TrayVolume::TrayVolume()
     : TrayImageItem(IDR_AURA_UBER_TRAY_VOLUME_MUTE),
+      volume_view_(NULL),
       is_default_view_(false) {
 }
 
 TrayVolume::~TrayVolume() {
 }
 
 bool TrayVolume::GetInitialVisibility() {
   return ash::Shell::GetInstance()->tray_delegate()->IsAudioMuted();
 }
 
 views::View* TrayVolume::CreateDefaultView(user::LoginStatus status) {
-  volume_view_.reset(new tray::VolumeView);
+  volume_view_ = new tray::VolumeView;
   is_default_view_ = true;
-  return volume_view_.get();
+  return volume_view_;
 }
 
 views::View* TrayVolume::CreateDetailedView(user::LoginStatus status) {
-  volume_view_.reset(new tray::VolumeView);
+  volume_view_ = new tray::VolumeView;
   is_default_view_ = false;
-  return volume_view_.get();
+  return volume_view_;
 }
 
 void TrayVolume::DestroyDefaultView() {
   if (is_default_view_)
-    volume_view_.reset();
+    volume_view_ = NULL;
 }
 
 void TrayVolume::DestroyDetailedView() {
   if (!is_default_view_)
-    volume_view_.reset();
+    volume_view_ = NULL;
 }
 
 void TrayVolume::OnVolumeChanged(float percent) {
   if (tray_view())
     tray_view()->SetVisible(GetInitialVisibility());
 
-  if (volume_view_.get()) {
+  if (volume_view_) {
     volume_view_->SetVolumeLevel(percent);
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
     return;
   }
   PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
 }
 
 }  // namespace internal
 }  // namespace ash