For the method webkit_dom_document_evaluate, parameter WebKitDOMXPathResult can be null. However this is not reflected in languages which use introspection and hence can not pass null value. Tried on Ubuntu 12.04 and 13.04 Desktop.
Created attachment 211653 [details] Patch This should be as simple as this.
Committed r155778: <http://trac.webkit.org/changeset/155778>