RenderWidgetHostViewChildFrame's called a virtual in its ctor.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 88daf80dcaf5e3e2f22c8a3f7fa8f47575df62f8..1595ab54316123951858ff2fe7f3538f82585195 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -888,7 +888,7 @@ bool RenderFrameHostImpl::CreateRenderFrame(int proxy_routing_id,
   // RenderWidgetHostImpl. https://crbug.com/545684
   if (parent_routing_id != MSG_ROUTING_NONE && render_widget_host_) {
     RenderWidgetHostView* rwhv =
-        new RenderWidgetHostViewChildFrame(render_widget_host_);
+        RenderWidgetHostViewChildFrame::Create(render_widget_host_);
     rwhv->Hide();
   }