Pull MessageListView into its own file for easier testing.

ui/message_center/views/message_center_view.h

 // Copyright (c) 2013 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_VIEWS_MESSAGE_CENTER_VIEW_H_
 #define UI_MESSAGE_CENTER_VIEWS_MESSAGE_CENTER_VIEW_H_
 
 
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/message_center/message_center_export.h"
 #include "ui/message_center/message_center_observer.h"
 #include "ui/message_center/notification_list.h"
 #include "ui/message_center/views/message_center_controller.h"
 #include "ui/message_center/views/message_view.h"
-#include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
 
 namespace gfx {
 class MultiAnimation;
 }  // namespace gfx
 
-namespace views {
-class Button;
-}  // namespace views
-
 namespace message_center {
 
 class MessageCenter;
-class MessageCenterBubble;
-class NotificationCenterButton;
 class MessageCenterButtonBar;
 class MessageCenterTray;
-class MessageCenterView;
 class MessageView;
 class MessageViewContextMenuController;
 class MessageListView;
 class NotificationView;
 class NotifierSettingsView;
 
-// MessageCenterView ///////////////////////////////////////////////////////////
-
+// Container for all the top-level views in the notification center, such as the
+// button bar, settings view, scrol view, and message list view.  Acts as a
+// controller for the message list view, passing data back and forth to message
+// center.
 class MESSAGE_CENTER_EXPORT MessageCenterView : public views::View,
                                                 public MessageCenterObserver,
                                                 public MessageCenterController,
                                                 public gfx::AnimationDelegate {
  public:
   MessageCenterView(MessageCenter* message_center,
                     MessageCenterTray* tray,
                     int max_height,
                     bool initially_settings_visible,
                     bool top_down,
@@ skipping 85 matching lines @@
   bool is_closing_;
 
   scoped_ptr<MessageViewContextMenuController> context_menu_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageCenterView);
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_VIEWS_MESSAGE_CENTER_VIEW_H_