[cssom] Figure out what to do with non-standard CSSStyleSheet methods in WebKit / Blink #3814
Description
WebKit / Blink implement some legacy Microsoft CSSOM functions on CSSStyleSheet, which if I'm not wrong come from Microsoft:
rulesjust callscssRules.removeRulejust callsdeleteRule.addRulejust string-concats a selector and a style block and callsinsertRule.
It's not too hard to add them to Gecko, but addRule in particular seems rather hacky / inconsistent with the rest of the APIs. We haven't seen any compat issue due to not having them (but I just got bit by it when trying to test something).
Would there be any chance on collecting data and potentially removing them? Or is all hope lost / is not worth the churn and should I just put them in the spec?