Make MessageCenter a singleton object and build on Windows.

chrome/browser/notifications/message_center_notification_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_
 #define CHROME_BROWSER_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/notifications/notification_ui_manager_impl.h"
 
 class Notification;
 class Profile;
 
+namespace message_center {
+class MessageCenter;
+}
+
 // This class extends NotificationUIManagerImpl and delegates actual display
 // of notifications to MessageCenter, doing necessary conversions.
 class MessageCenterNotificationManager : public NotificationUIManagerImpl {
  public:
   MessageCenterNotificationManager();
   virtual ~MessageCenterNotificationManager();
 
   // NotificationUIManager:
   virtual bool CancelById(const std::string& notification_id) OVERRIDE;
   virtual bool CancelAllBySourceOrigin(const GURL& source_origin) OVERRIDE;
   virtual bool CancelAllByProfile(Profile* profile) OVERRIDE;
   virtual void CancelAll() OVERRIDE;
 
   // NotificationUIManagerImpl:
   virtual bool ShowNotification(const Notification& notification,
                                 Profile* profile) OVERRIDE;
   virtual bool UpdateNotification(const Notification& notification) OVERRIDE;
 
  private:
+  message_center::MessageCenter* message_center_;
+
   DISALLOW_COPY_AND_ASSIGN(MessageCenterNotificationManager);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_MESSAGE_CENTER_NOTIFICATION_MANAGER_H_