Similar to the NodeFilter case (see bug #93002), but in this case the XPathNSResolver interface can be implemented internally or by the application. So we need to expose it as an interface, but we also need to wrap NativeXPathNSResolver internally to provide a default implementation for methods that create a XPathNSResolver.
Created attachment 233696 [details] Patch
Created attachment 233804 [details] Updated to build on current git master
Comment on attachment 233804 [details] Updated to build on current git master LGTM
Committed r170700: <http://trac.webkit.org/changeset/170700>