After r150214, (bug 116185) Page::chrome() now returns a reference, but not all code was adapted to handle this. In particular this breaks the GTK+ debug builds.
Created attachment 202080 [details] Patch
Created attachment 202087 [details] Patch
I noticed that Gustavo fixed the GTK+ part in r150256. I've just uploaded an updated patch without that file.
Comment on attachment 202087 [details] Patch Clearing flags on attachment: 202087 Committed r150263: <http://trac.webkit.org/changeset/150263>
All reviewed patches have been landed. Closing bug.