It's no longer used in GTK3 build and breaks the GTK4 build since the API has been removed.
Pull request: https://github.com/WebKit/WebKit/pull/8454
Committed 258715@main (b48ba57fb5ed): <https://commits.webkit.org/258715@main> Reviewed commits have been landed. Closing PR #8454 and removing active labels.
<rdar://problem/104070807>