We need to define a guard that clients of WKWindowProxyProperty can consume so that embedders that use both old and new SDKs can use the enum.
<rdar://problem/119684456>
Pull request: https://github.com/WebKit/WebKit/pull/21825
Committed 272077@main (c553c8ec6dc3): <https://commits.webkit.org/272077@main> Reviewed commits have been landed. Closing PR #21825 and removing active labels.