This does quite a bit of work. Avoid unnecessary calls.
Created attachment 331047 [details] wip
Created attachment 331049 [details] wip
Created attachment 331051 [details] patch
Created attachment 331091 [details] patch
Comment on attachment 331091 [details] patch Clearing flags on attachment: 331091 Committed r226809: <https://trac.webkit.org/changeset/226809>
All reviewed patches have been landed. Closing bug.
<rdar://problem/36450650>