NotificationController::clientFrom() should return a reference

Source/modules/notifications/NotificationController.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 27 matching lines @@
 
 NotificationController::~NotificationController()
 {
 }
 
 PassOwnPtr<NotificationController> NotificationController::create(PassOwnPtr<NotificationClient> client)
 {
     return adoptPtr(new NotificationController(client));
 }
 
-NotificationClient* NotificationController::clientFrom(LocalFrame* frame)
+NotificationClient& NotificationController::clientFrom(LocalFrame* frame)
 {
-    if (NotificationController* controller = NotificationController::from(frame))
-        return controller->client();
-    return 0;
+    NotificationController* controller = NotificationController::from(frame);
+    ASSERT(controller);
+    return controller->client();
 }
 
 const char* NotificationController::supplementName()
 {
     return "NotificationController";
 }
 
 void provideNotification(LocalFrame& frame, PassOwnPtr<NotificationClient> client)
 {
     NotificationController::provideTo(frame, NotificationController::supplementName(), NotificationController::create(client));
 }
 
 } // namespace WebCore