https://drafts.csswg.org/mediaqueries-4/#hover
https://drafts.csswg.org/mediaqueries-4/#pointer

In this patch series, we don't introduce any-hover and any-pointer media
features yet, but functionalities for them on each platform backends will be
introduced in this patch series, so eIntID_AllPointerCapabilities and relevant
stuff is added in this patch for the convenience that each platform backends
can be reviewed at once.

Differential Revision: https://phabricator.services.mozilla.com/D3296