Document::isSafeToUpdateStyleOrLayout() can tell whether it is safe to run layout.
rdar://problem/36365706
Created attachment 331426 [details] Patch
Comment on attachment 331426 [details] Patch Clearing flags on attachment: 331426 Committed r227006: <https://trac.webkit.org/changeset/227006>
All reviewed patches have been landed. Closing bug.