mash: Convert WebNotificationTray to wm common types

chrome/browser/ui/views/message_center/web_notification_tray.cc

 // Copyright 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/ui/views/message_center/web_notification_tray.h"
 
 #include "chrome/browser/browser_process.h"
 #include "ui/display/screen.h"
 #include "ui/message_center/message_center_tray.h"
 #include "ui/message_center/message_center_tray_delegate.h"
 #include "ui/message_center/views/desktop_popup_alignment_delegate.h"
 #include "ui/message_center/views/message_popup_collection.h"
 
 namespace message_center {
 
 MessageCenterTrayDelegate* CreateMessageCenterTray() {
   return new WebNotificationTray();
 }
 
 WebNotificationTray::WebNotificationTray() {
   message_center_tray_.reset(
       new MessageCenterTray(this, g_browser_process->message_center()));
   alignment_delegate_.reset(new message_center::DesktopPopupAlignmentDelegate);
   popup_collection_.reset(new message_center::MessagePopupCollection(
-      NULL, message_center(), message_center_tray_.get(),
-      alignment_delegate_.get()));
+      message_center(), message_center_tray_.get(), alignment_delegate_.get()));
 }
 
 WebNotificationTray::~WebNotificationTray() {
   // Reset this early so that delegated events during destruction don't cause
   // problems.
   popup_collection_.reset();
   message_center_tray_.reset();
 }
 
 message_center::MessageCenter* WebNotificationTray::message_center() {
@@ skipping 31 matching lines @@
 }
 
 void WebNotificationTray::OnMessageCenterTrayChanged() {
 }
 
 MessageCenterTray* WebNotificationTray::GetMessageCenterTray() {
   return message_center_tray_.get();
 }
 
 }  // namespace message_center