_addLog is an asynchronous function, we should treat it as one in ValidateChange.
<rdar://problem/104977612>
Pull request: https://github.com/WebKit/WebKit/pull/9554
Committed 259782@main (1c9d439b0c6b): <https://commits.webkit.org/259782@main> Reviewed commits have been landed. Closing PR #9554 and removing active labels.