[css-contain] Applicability size containment, layout containment and paint containment to internal ruby elements

[frivoal]

size containment, layout containment and paint containment are defined not to apply to internal table elements (with an exception for paint containment on table-cells).

I believe this should be extended to exclude internal ruby elements as well from all 3 of size containment, layout containment and paint containment.

[css-meeting-bot]

The Working Group just discussed https://github.com/w3c/csswg-drafts/issues/2223, and agreed to the following resolutions:

• RESOLVED: size layout and paint don't apply to internal ruby elements.

The full IRC log of that discussion

<dael> Topic: https://github.com//issues/2223
<dael> github: https://github.com//issues/2512
<dael> florian: Size containment, layout containment and paint continment don't apply to internal layout parts. But we don't say anything about internal ruby elements. We should exclude those as well.
<dael> koji: What's internal ruby elements?
<dael> florian: Things like ruby-base container and ruby-text container. Layout containment on these things doesn't make a whole lot of sense. I
<dael> ??: It would apply ruby element
<dael> florian: Yes.
<dael> dbaron: I'm fine with that.
<dael> Rossen: Any reasons we should be applying containment?
<dael> RESOLVED: size layout and paint don't apply to internal ruby elements.