According to the FIXME comment in WKPageSetInvalidMessageFunction, we can remove this function when doing so won't break the nightlies.
Created attachment 239447 [details] Patch
Comment on attachment 239447 [details] Patch Clearing flags on attachment: 239447 Committed r174415: <http://trac.webkit.org/changeset/174415>
All reviewed patches have been landed. Closing bug.