Identifier::string() should return an AtomString instead of a String, since it holds an AtomString internally.
Pull request: https://github.com/WebKit/WebKit/pull/524
Committed r293879 (250337@main): <https://commits.webkit.org/250337@main> Reviewed commits have been landed. Closing PR #524 and removing active labels.
<rdar://problem/92835710>