In RecordContentView.js _updateCanvasPath() should not be called if CanvasPathDebugging is not supported otherwise _updateCanvasPath() tries to access _showPathButtonNavigationItem, which is created only if CanvasPathDebugging is supported, but fails and raises an exception.
Created attachment 400414 [details] Patch
Comment on attachment 400414 [details] Patch r=me, good catch!
(In reply to Devin Rousso from comment #2) > Comment on attachment 400414 [details] > Patch > > r=me, good catch! Thank you for the prompt review :)
Committed r262230: <https://trac.webkit.org/changeset/262230> All reviewed patches have been landed. Closing bug and clearing flags on attachment 400414 [details].
<rdar://problem/63699679>