Stop marking isInvalidInputType() as friend to InputType subclasses. We just need to make a few validation function public (which they are already in the base class). This allows us to move isInvalidInputType() to InputType.cpp, since this is the only place it is used.
Pull request: https://github.com/WebKit/WebKit/pull/12975
Committed 263179@main (5b1d7c243102): <https://commits.webkit.org/263179@main> Reviewed commits have been landed. Closing PR #12975 and removing active labels.
<rdar://problem/108325034>