Implement message center on Windows

ui/message_center/message_center.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 "ui/message_center/message_center.h"
 
 #include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 
 namespace message_center {
 
 //------------------------------------------------------------------------------
 
-// static
-MessageCenter* MessageCenter::GetInstance() {
-  return Singleton<MessageCenter>::get();
+MessageCenter::MessageCenter()
+    : delegate_(NULL) {
+  notification_list_.reset(new NotificationList(this));
 }
 
 MessageCenter::~MessageCenter() {
   notification_list_.reset();
 }
 
 void MessageCenter::AddObserver(Observer* observer) {
   observer_list_.AddObserver(observer);
 }
 
@@ skipping 137 matching lines @@
   return notification_list_.get();
 }
 
 void MessageCenter::Delegate::OnButtonClicked(const std::string& id,
                                               int button_index) {
 }
 
 //------------------------------------------------------------------------------
 // Private.
 
-MessageCenter::MessageCenter()
-    : delegate_(NULL) {
-  notification_list_.reset(new NotificationList(this));
-}
-
 void MessageCenter::NotifyMessageCenterChanged(bool new_notification) {
   FOR_EACH_OBSERVER(Observer,
                     observer_list_,
                     OnMessageCenterChanged(new_notification));
 }
 
 
 }  // namespace message_center