Transfer responsibility for providing a close button for a notification to each implementation of M…

ui/arc/notification/arc_custom_notification_view.h

 // Copyright 2016 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_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_
 #define UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "ui/arc/notification/arc_custom_notification_item.h"
 #include "ui/arc/notification/arc_notification_surface_manager.h"
 #include "ui/aura/window_observer.h"
+#include "ui/message_center/views/custom_notification_content_view_delegate.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/native/native_view_host.h"
 
 namespace exo {
 class NotificationSurface;
 }
 
 namespace views {
 class ImageButton;
 class Widget;
 }
 
 namespace arc {
 
 class ArcCustomNotificationView
     : public views::NativeViewHost,
       public views::ButtonListener,
       public aura::WindowObserver,
       public ArcCustomNotificationItem::Observer,
       public ArcNotificationSurfaceManager::Observer {
  public:
   explicit ArcCustomNotificationView(ArcCustomNotificationItem* item);
   ~ArcCustomNotificationView() override;
 
+  std::unique_ptr<message_center::CustomNotificationContentViewDelegate>
+  CreateContentViewDelegate();
+
  private:
+  class ContentViewDelegate;
   class EventForwarder;
   class SlideHelper;
 
   void CreateFloatingCloseButton();
   void SetSurface(exo::NotificationSurface* surface);
   void UpdatePreferredSize();
   void UpdateCloseButtonVisiblity();
   void UpdatePinnedState();
   void UpdateSnapshot();
   void AttachSurface();
@@ skipping 51 matching lines @@
 
   // Protects from call loops between Layout and OnWindowBoundsChanged.
   bool in_layout_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(ArcCustomNotificationView);
 };
 
 }  // namespace arc
 
 #endif  // UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_