CustomElementRegistry.define was throwing a JavaScript syntax error instead of a DOM syntax error
Created attachment 323107 [details] Patch
Created attachment 323112 [details] Patch
Comment on attachment 323112 [details] Patch Clearing flags on attachment: 323112 Committed r223032: <http://trac.webkit.org/changeset/223032>
All reviewed patches have been landed. Closing bug.
<rdar://problem/34876055>