Add presubmit check for scoped_ptr usage.

ui/message_center/views/toast_contents_view.cc

 // 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 "ui/message_center/views/toast_contents_view.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 289 matching lines @@
   if (collection_)
     collection_->RemoveNotification(notification_id, by_user);
 }
 
 scoped_ptr<ui::MenuModel> ToastContentsView::CreateMenuModel(
       const NotifierId& notifier_id,
       const base::string16& display_source) {
   // Should not reach, the context menu should be handled in
   // MessagePopupCollection.
   NOTREACHED();
-  return scoped_ptr<ui::MenuModel>();
+  return nullptr;
 }
 
 bool ToastContentsView::HasClickedListener(
     const std::string& notification_id) {
   if (!collection_)
     return false;
   return collection_->HasClickedListener(notification_id);
 }
 
 void ToastContentsView::ClickOnNotificationButton(
@@ skipping 25 matching lines @@
 }
 
 gfx::Rect ToastContentsView::GetClosedToastBounds(gfx::Rect bounds) {
   return gfx::Rect(bounds.x() + bounds.width() - kClosedToastWidth,
                    bounds.y(),
                    kClosedToastWidth,
                    bounds.height());
 }
 
 }  // namespace message_center