<rdar://problem/15560240> ArgumentCoder<ResourceError>::encodePlatformData() encodes only string-valued keys in the NSError’s userInfo dictionary. In particular, it doesn’t encode the value of NSErrorFailingURLKey, which is an NSURL.
Created attachment 218083 [details] Encode all string- and URL-valued keys in the user info dictionary
Fixed in <http://trac.webkit.org/r159887>.