Parameter to input.setCustomValidity() should not be nullable: - https://html.spec.whatwg.org/#htmlinputelement Firefox and Chrome agree with the specification so the change should be safe.
Created attachment 303764 [details] Patch
Comment on attachment 303764 [details] Patch Clearing flags on attachment: 303764 Committed r213606: <http://trac.webkit.org/changeset/213606>
All reviewed patches have been landed. Closing bug.