Let's add experimental support for CSS Color 5 color-contrast() - https://drafts.csswg.org/css-color-5/#colorcontrast. Because the spec doesn't seem quite finished, we should keep this behind an experimental feature flag for now.
Created attachment 421781 [details] Patch
Created attachment 421787 [details] Patch
Created attachment 421829 [details] Patch
Committed r273683: <https://commits.webkit.org/r273683> All reviewed patches have been landed. Closing bug and clearing flags on attachment 421829 [details].
<rdar://problem/74886031>