Created by: cvrebert
I propose adding these on the grounds that <dialog> would make it much easier and less hacky to implement modals. In particular, accomplishing the "disablement" of the underlying page, so that the modal is actually modal, is currently pretty painful.
Refs:
- https://bugzil.la/840640
- https://webkit.org/b/84635
- http://caniuse.com/#feat=dialog
- https://html.spec.whatwg.org/multipage/forms.html#the-dialog-element
CC: @twbs/team for review