Prevents crashing on launch in Safari.
Created attachment 387959 [details] Patch
Comment on attachment 387959 [details] Patch Clearing flags on attachment: 387959 Committed r254723: <https://trac.webkit.org/changeset/254723>
All reviewed patches have been landed. Closing bug.
Filed: Bug 206394 – [WinCairo][WK2] ASSERT(isUIThread()) is failing since r254723
<rdar://problem/58669977>