Clearing a registration should null out its workers before setting their state to "redundant". This seems to match Firefox and Chrome.
<rdar://problem/37142874>
Created attachment 332933 [details] Patch
Created attachment 332934 [details] Patch
Comment on attachment 332934 [details] Patch Clearing flags on attachment: 332934 Committed r228015: <https://trac.webkit.org/changeset/228015>
All reviewed patches have been landed. Closing bug.