It is not safe to handle this on a non main thread, since we send messages to the WebContent and GPU process.
Pull request: https://github.com/WebKit/WebKit/pull/1576
Committed r295600 (251605@main): <https://commits.webkit.org/251605@main> Reviewed commits have been landed. Closing PR #1576 and removing active labels.
<rdar://problem/95315035>