For some odd reason qwebpreferences has been implemented using the C-API. It makes it hard to read and maintain, and is unnecessarily demented.
Created attachment 170161 [details] Patch
Comment on attachment 170161 [details] Patch Clearing flags on attachment: 170161 Committed r132222: <http://trac.webkit.org/changeset/132222>
All reviewed patches have been landed. Closing bug.