Thee fields are computed based on the FontDescription. They're only mutable because we also update them in FontCascade::updateFonts(), but that function only updates the FontCascadeFonts pointer, not the FontDescription. So there should be no need to update them at that time.
Pull request: https://github.com/WebKit/WebKit/pull/1569
Committed r295619 (251624@main): <https://commits.webkit.org/251624@main>
Reviewed commits have been landed. Closing PR #1569 and removing active labels.