When Lookup can't provide a range, it sometimes returns (NSNotFound, 0), and other times, (0, 0).
In the latter case, we somehow build a single character string.
Created attachment 281916 [details]
Created attachment 281917 [details]
Forgot to update a FIXME.
Comment on attachment 281917 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=281917&action=review
> + // FIXME (159063): We shouldn't need to check for zero lenght here.