Second parameter to MutationObserver.observe() should be optional: - https://dom.spec.whatwg.org/#interface-mutationobserver
Created attachment 289990 [details] Patch
Comment on attachment 289990 [details] Patch Clearing flags on attachment: 289990 Committed r206453: <http://trac.webkit.org/changeset/206453>
All reviewed patches have been landed. Closing bug.