https://drafts.csswg.org/css-fonts/#om-fontfeaturevalues Says we should have the FONT_FEATURE_VALUES_RULE constant.
<rdar://problem/102017360>
Pull request: https://github.com/WebKit/WebKit/pull/6192
Committed 256380@main (713b0baf74e8): <https://commits.webkit.org/256380@main> Reviewed commits have been landed. Closing PR #6192 and removing active labels.