Move message_center::CustomNotificationView to arc::ArcNotificationView

ui/message_center/notification_delegate.h

Index: ui/message_center/notification_delegate.h
diff --git a/ui/message_center/notification_delegate.h b/ui/message_center/notification_delegate.h
index a66d3760e690d8c03458ee9266f1be928a03269c..dd6f4cd2df9836f68e5b996a5ad2297f4a75d2b0 100644
--- a/ui/message_center/notification_delegate.h
+++ b/ui/message_center/notification_delegate.h
@@ -14,12 +14,12 @@
 #include "base/strings/string16.h"
 #include "ui/message_center/message_center_export.h"
 
-#if defined(TOOLKIT_VIEWS) && !defined(OS_MACOSX)
-#include "ui/message_center/views/custom_notification_content_view_delegate.h"
-#endif
-
 namespace message_center {
 
+class MessageCenterController;
+class MessageView;
+class Notification;
+
 // Delegate for a notification. This class has two roles: to implement callback
 // methods for notification, and to provide an identity of the associated
 // notification.
@@ -56,9 +56,11 @@ class MESSAGE_CENTER_EXPORT NotificationDelegate
   virtual bool ShouldDisplaySettingsButton();
 
 #if defined(TOOLKIT_VIEWS) && !defined(OS_MACOSX)

[hidehiko, 2017/05/11 14:22:47]

(Optional) Is this guard still necessary? Ditto for caller. If so, probably it
is good to be documented here.

[yoshiki, 2017/05/12 08:42:38]

I think this condition is obvious since this returns a view and mac chrome
doesn't support views notification.

-  // To be called to construct the contents view of a popup for notifications
-  // whose type is NOTIFICATION_TYPE_CUSTOM.
-  virtual std::unique_ptr<CustomContent> CreateCustomContent();
+  // To be called to construct the message view for notifications whose type is
+  // NOTIFICATION_TYPE_CUSTOM.
+  virtual std::unique_ptr<MessageView> CreateCustomMessageView(
+      MessageCenterController* controller,
+      const Notification& notification);
 #endif
 
   // Indicates whether this notification should be displayed when there is