The WidgetBackingStoreGtkX11 is used only under certain conditions, but it is compiled unconditionally, which can cause a build break eventually.
Created attachment 240282 [details] proposed wk patch
Comment on attachment 240282 [details] proposed wk patch Thanks!
Comment on attachment 240282 [details] proposed wk patch Clearing flags on attachment: 240282 Committed r175087: <http://trac.webkit.org/changeset/175087>
All reviewed patches have been landed. Closing bug.