[css-contain-3] Should not cq units be interpreted in the flatDom context? #7947
Description
It looks like the cqw value is interpreted within the logical Dom context, and not the flatDom context. And this behavior seems to differ from the behavior of at least two other relative css units: % and em. Here is a test that illustrate the issue (only a single line of code is different in the last three tests):
https://jsfiddle.net/fcx7rv2a/ (uses cqw directly)
https://jsfiddle.net/0hfnpumq/1/
https://jsfiddle.net/0hfnpumq/2/
https://jsfiddle.net/0hfnpumq/3/
Have I misunderstood something here? Or is this expected behavior?