Notificaitons refactor step 2

ui/message_center/message_view.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 UI_MESSAGE_CENTER_MESSAGE_VIEW_H_
 #define UI_MESSAGE_CENTER_MESSAGE_VIEW_H_
 
 #include "ui/message_center/notification.h"
 #include "ui/message_center/notification_list.h"
 #include "ui/views/controls/button/button.h"
@@ skipping 12 matching lines @@
 const int kPaddingHorizontal = 18;
 const int kWebNotificationButtonWidth = 32;
 const int kWebNotificationIconSize = 40;
 const int kWebNotificationWidth = 300;
 
 // An abstract class that forms the basis of a view for a notification entry.
 class MessageView : public views::SlideOutView,
                     public views::ButtonListener {
  public:
   MessageView(NotificationList::Delegate* list_delegate,
-              const Notification& notification);
+              Notification* notification);
 
   virtual ~MessageView();
 
   // Creates the elements that make up the view layout. Must be called
   // immediately after construction.
   virtual void SetUpView() = 0;
 
   void set_scroller(views::ScrollView* scroller) { scroller_ = scroller; }
 
   // Overridden from views::View.
   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
 
   // Overridden from ui::EventHandler.
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from ButtonListener.
   virtual void ButtonPressed(views::Button* sender,
                              const ui::Event& event) OVERRIDE;
 
  protected:
   MessageView();
 
   // Shows the menu for the notification.
   void ShowMenu(gfx::Point screen_location);
 
   // Overridden from views::SlideOutView.
   virtual void OnSlideOut() OVERRIDE;
 
   NotificationList::Delegate* list_delegate() { return list_delegate_; }
-  Notification& notification() { return notification_; }
+  Notification* notification() { return notification_; }
   views::ImageButton* close_button() { return close_button_.get(); }
   views::ScrollView* scroller() { return scroller_; }
 
  private:
-  NotificationList::Delegate* list_delegate_;
-  Notification notification_;
+  NotificationList::Delegate* list_delegate_; // Weak, global (MessageCenter).
+  Notification* notification_; // Weak, owned by NotificationList.
   scoped_ptr<views::ImageButton> close_button_;
 
   views::ScrollView* scroller_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageView);
 };
 
 }  // namespace message_center
 
 #endif // UI_MESSAGE_CENTER_MESSAGE_VIEW_H_