It just needs to be ported.
Created attachment 400319 [details] Patch
Thanks for the patch. If this patch contains new public API please make sure it follows the guidelines for new WebKit2 GTK+ API. See http://trac.webkit.org/wiki/WebKitGTK/AddingNewWebKit2API
Created attachment 400449 [details] Patch
Committed r262286: <https://trac.webkit.org/changeset/262286>