They don't do anything since r164235. All possible solutions I can think of to implement this should be done in the application side. So, I think it's better to deprecated instead of trying to figure out how to re-implement them in webkit without the view source mode in webcore.
Created attachment 225044 [details]
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 225049 [details]
Forgot to add deprecation guards in public header
Committed r164634: <http://trac.webkit.org/changeset/164634>