[css-nav-1] Box tree? Element tree? Fragment tree? etc #3359
Description
Migrated from WICG/spatial-navigation#47
Originally created by @frivoal on Tue, 03 Apr 2018 07:30:48 GMT
We should do a thorough review of the processing model, to make sure that it consistently and correctly uses the correct tree (element tree vs box tree vs fragment tree...) and the correct ancestry relationships (parent vs containing block).