WidgetDelegateView is its own contents view.

ui/views/widget/widget_delegate.cc

 // Copyright (c) 2012 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/views/widget/widget_delegate.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/view.h"
 #include "ui/views/views_delegate.h"
@@ skipping 186 matching lines @@
 }
 
 Widget* WidgetDelegateView::GetWidget() {
   return View::GetWidget();
 }
 
 const Widget* WidgetDelegateView::GetWidget() const {
   return View::GetWidget();
 }
 
+views::View* WidgetDelegateView::GetContentsView() {
+  return this;
+}
+
 const char* WidgetDelegateView::GetClassName() const {
   return kViewClassName;
 }
 
 }  // namespace views