RenderWidgetHostViewChildFrame's called a virtual in its ctor.

content/browser/web_contents/web_contents_view_guest.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 "content/browser/web_contents/web_contents_view_guest.h"
 
 #include <utility>
 
 #include "build/build_config.h"
 #include "content/browser/browser_plugin/browser_plugin_embedder.h"
@@ skipping 130 matching lines @@
     // view twice), we check for the RVH Factory, which will be set when we're
     // making special ones (which go along with the special views).
     DCHECK(RenderViewHostFactory::has_factory());
     return static_cast<RenderWidgetHostViewBase*>(
         render_widget_host->GetView());
   }
 
   RenderWidgetHostViewBase* platform_widget =
       platform_view_->CreateViewForWidget(render_widget_host, true);
 
-  return new RenderWidgetHostViewGuest(render_widget_host,
-                                       guest_,
-                                       platform_widget->GetWeakPtr());
+  return RenderWidgetHostViewGuest::Create(render_widget_host, guest_,
+                                           platform_widget->GetWeakPtr());
 }
 
 RenderWidgetHostViewBase* WebContentsViewGuest::CreateViewForPopupWidget(
     RenderWidgetHost* render_widget_host) {
   return platform_view_->CreateViewForPopupWidget(render_widget_host);
 }
 
 void WebContentsViewGuest::SetPageTitle(const base::string16& title) {
 }
 
@@ skipping 77 matching lines @@
       embedder_render_view_host->GetDelegate()->GetDelegateView();
   if (view) {
     RecordAction(base::UserMetricsAction("BrowserPlugin.Guest.StartDrag"));
     view->StartDragging(drop_data, ops, image, image_offset, event_info);
   } else {
     embedder_web_contents->SystemDragEnded();
   }
 }
 
 }  // namespace content