https://bugs.webkit.org/show_bug.cgi?id=233330 claims that duplicate sub domains such as news.news.example.com causes WebKit's RegistrableDomain matching to fail and treat same-site content as cross-site. We should add tests of such duplicate sub domains.
<rdar://problem/86130326>
Created attachment 446097 [details] Patch for landing
Committed r286582 (?): <https://commits.webkit.org/r286582> All reviewed patches have been landed. Closing bug and clearing flags on attachment 446097 [details].