It crashes with an Objective-C exception.
Created attachment 390376 [details] Patch
The commit-queue encountered the following flaky tests while processing attachment 390376 [details]: editing/spelling/spellcheck-async-remove-frame.html bug 158401 (authors: morrita@google.com, rniwa@webkit.org, and tony@chromium.org) imported/w3c/web-platform-tests/IndexedDB/fire-success-event-exception.html bug 206554 (authors: shvaikalesh@gmail.com and youennf@gmail.com) The commit-queue is continuing to process your patch.
Comment on attachment 390376 [details] Patch Clearing flags on attachment: 390376 Committed r256343: <https://trac.webkit.org/changeset/256343>
All reviewed patches have been landed. Closing bug.
<rdar://problem/59360111>