Move NotificationDelegate into message_center.

chrome/browser/notifications/notification_delegate.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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.
 
 #include "chrome/browser/notifications/notification_delegate.h"
 
-bool NotificationDelegate::HasClickedListener() {
-  return false;
-}
+int NotificationDelegate::process_id() const { return -1; }
 
-void NotificationDelegate::ButtonClick(int button_index) {
-}
-
-int NotificationDelegate::process_id() const {
-  return -1;
-}
-
-void NotificationDelegate::ReleaseRenderViewHost() {
-}
+void NotificationDelegate::ReleaseRenderViewHost() {}