RenderWidgetHostViewChildFrame's called a virtual in its ctor.

content/browser/web_contents/web_contents_view_child_frame.cc

 // Copyright (c) 2016 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_child_frame.h"
 
 #include "build/build_config.h"
 #include "content/browser/frame_host/render_widget_host_view_child_frame.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents_view_delegate.h"
@@ skipping 69 matching lines @@
 }
 
 void WebContentsViewChildFrame::CreateView(const gfx::Size& initial_size,
                                            gfx::NativeView context) {
   // The WebContentsViewChildFrame does not have a native view.
 }
 
 RenderWidgetHostViewBase* WebContentsViewChildFrame::CreateViewForWidget(
     RenderWidgetHost* render_widget_host,
     bool is_guest_view_hack) {
-  return new RenderWidgetHostViewChildFrame(render_widget_host);
+  return RenderWidgetHostViewChildFrame::Create(render_widget_host);
 }
 
 RenderWidgetHostViewBase* WebContentsViewChildFrame::CreateViewForPopupWidget(
     RenderWidgetHost* render_widget_host) {
   return GetOuterView()->CreateViewForPopupWidget(render_widget_host);
 }
 
 void WebContentsViewChildFrame::SetPageTitle(const base::string16& title) {
   // The title is ignored for the WebContentsViewChildFrame.
 }
@@ skipping 64 matching lines @@
 void WebContentsViewChildFrame::StartDragging(
     const DropData& drop_data,
     WebDragOperationsMask ops,
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
     const DragEventSourceInfo& event_info) {
   NOTREACHED();
 }
 
 }  // namespace content