WidgetDelegateView is its own contents view.

chrome/browser/chromeos/ui/kiosk_external_update_notification.cc

 // Copyright 2014 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/chromeos/ui/kiosk_external_update_notification.h"
 
 #include "ash/common/shell_window_ids.h"
 #include "ash/shell.h"
 #include "base/macros.h"
 #include "ui/aura/window.h"
@@ skipping 123 matching lines @@
   params.ownership = views::Widget::InitParams::NATIVE_WIDGET_OWNS_WIDGET;
   params.accept_events = false;
   params.keep_on_top = true;
   params.remove_standard_frame = true;
   params.delegate = view_;
   params.bounds = bounds;
   params.parent = ash::Shell::GetContainer(
       root_window, ash::kShellWindowId_SettingBubbleContainer);
   views::Widget* widget = new views::Widget;
   widget->Init(params);
-  widget->SetContentsView(view_);
   gfx::NativeView native_view = widget->GetNativeView();
   native_view->SetName("KioskExternalUpdateNotification");
   widget->Show();
 }
 
 void KioskExternalUpdateNotification::Dismiss() {
   if (view_) {
     KioskExternalUpdateNotificationView* view = view_;
     view_ = NULL;
     view->CloseByOwner();
   }
 }
 
 }  // namespace chromeos