Defining fontBoundingBoxAscent/fontBoundingBoxDescent

[yiyix]

I am trying to update the implementation note for the definition of fontBoundingBoxAscent and fontBoundingBoxDescent. After a discussion with dbaron@ and jfkthame@, I wrote the following:

The Implementations of fontBoundingBoxAscent fontBoundingBoxDescent are expected to be equivalent to that of "sTypoAscender" and "sTypoDescender" in OpenType Specification OS/2 table. If these are not available, implementations returns "ascender" and "descender" in hhea table.

ref: #5429

Could we confirm this is how is defined in CSS?

Thank you very much

[annevk]

cc @dbaron @jfkthame @whatwg/css

[annevk]

This got resolved in #5429 after all. w3c/csswg-drafts#5266 ensures that it doesn't regress, so I think we can close this.