[css-typed-om] ratio

[OliverJAsh]

Relevant spec: https://www.w3.org/TR/css-typed-om-1/

Currently it doesn't seem possible to parse aspect-ratio:

console.log(CSSStyleValue.parse('aspect-ratio', '1 / 2'))
// => CSSStyleValue

Would it make sense to create a new subclass of CSSStyleValue to capture the <ratio> type? E.g. CSSRatioValue.

(Apologies if I've filed this issue in the wrong place.)