checkLoaded() does not exist in the common parent class (StyleSheet), so it shouldn't be virtual in the CSS/XSL StyleSheets.
Created attachment 116673 [details] Patch
Comment on attachment 116673 [details] Patch Wish these had a better name/were factored differently.
Comment on attachment 116673 [details] Patch Clearing flags on attachment: 116673 Committed r101206: <http://trac.webkit.org/changeset/101206>
All reviewed patches have been landed. Closing bug.