WebKit layout translates painter, how to get offset?

When a widget is created for a MediaRenderer under an HTMLMediaElement, etc. and the page is then re-layed out, the widgets don't actually get moved, but an offset is applied to the "system painter" so that when the widget is rendered, the rendering gets translated by the layout offset. This works fine internally, but doesn't work if, for example, the widget is a place holder for another graphics h/w plane (i.e. a video plane) that is supposed to show underneath the widget.

I tried simply moving the widget to the new layout, but that messes up a lot more inside webkit. Is there a clean (i.e Qt) way to get whatever layout offset is applied to the "sharedpainter" inside the actual widget's paint event handler? It seems hidden on purpose and for now I am having to hand message (read hack) the offset down from the HTML/Media render paint to the backing widget but it would be nice to know what the proper thing to do would be. Sorry for typical newbie language.