I originally posted this on https://chromium-review.googlesource.com/c/chromium/src/+/981956, but figured it'd be a good idea to file a bug in case the CL doesn't get looked at.

That patch was merged, but its corresponding web-platform-tests pull request is still open: https://github.com/w3c/web-platform-tests/pull/10191

Looking at the logs there, Firefox isn't working with those changes:

    PID 10357 | JavaScript error: http://web-platform.test:8000/css/css-typed-om/the-stylepropertymap/properties/resources/testsuite.js, line 22: ReferenceError: CSSKeywordValue is not defined
    PID 10357 | JavaScript error: http://web-platform.test:8000/css/css-typed-om/the-stylepropertymap/properties/resources/testsuite.js, line 334: ReferenceError: can't access lexical declaration `gCssWideKeywordsExamples' before initialization

Can someone take a look and see if there's a compatibility issue here?