No need to re-construct it on every layout frame.
<rdar://problem/57227259>
Created attachment 383616 [details] Patch
Created attachment 383618 [details] Patch
Created attachment 383619 [details] Patch
Created attachment 383621 [details] Patch
Comment on attachment 383621 [details] Patch Clearing flags on attachment: 383621 Committed r252487: <https://trac.webkit.org/changeset/252487>
All reviewed patches have been landed. Closing bug.