Deprecate per notification type delegates.

chrome/browser/notifications/message_center_display_service.cc

Index: chrome/browser/notifications/message_center_display_service.cc
diff --git a/chrome/browser/notifications/message_center_display_service.cc b/chrome/browser/notifications/message_center_display_service.cc
index e04fca35462b7f732e4640d8127925161ddd158e..e7445d73310896bf6cbe655d3ad822330a9f73d6 100644
--- a/chrome/browser/notifications/message_center_display_service.cc
+++ b/chrome/browser/notifications/message_center_display_service.cc
@@ -8,9 +8,11 @@
 #include "chrome/browser/notifications/message_center_display_service.h"
 
 #include "chrome/browser/notifications/notification.h"
+#include "chrome/browser/notifications/notification_handler.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_event_dispatcher.h"
 
 MessageCenterDisplayService::MessageCenterDisplayService(
     Profile* profile,
@@ -28,6 +30,9 @@ void MessageCenterDisplayService::Display(
   // TODO(miguelg): MCDS should stop relying on the |notification|'s delegate
   // for Close/Click operations once the Notification object becomes a mojom
   // type.
+
+  NotificationHandler* handler = GetNotificationHandler(notification_type);
+  handler->OnShow(profile_, notification_id);
   ui_manager_->Add(notification, profile_);
 }