protocol://host:port/ is not a parsed KURL string when protocol is http, and port is 80. This constructor is not used in WebCore normally, but is exposed through API.
Created attachment 196530 [details] proposed fix
Comment on attachment 196530 [details] proposed fix r=me
Committed <http://trac.webkit.org/r147671>.
Thanks for the fix ap/ggaren. Sorry for the trouble.