[mediaqueries] device-width media feature and privacy

[zcorpan]

https://drafts.csswg.org/mediaqueries/#descdef-media-device-width

See https://www.w3.org/Bugs/Public/show_bug.cgi?id=29577

resulting in

dc36ecd

MQ spec should replace "screen" with "Web-exposed screen area" (xref cssom-view, or we can move the definition somewhere else).

cc @cvrebert

[zcorpan]

I suppose this would also affect 'device-aspect-ratio'...

[frivoal]

Aligning with cssom-view on this makes sense to me.

Besides, those media queries are deprecated anyway, so I have no particular qualm about tweaking them, especially to protect privacy.

[cvrebert]

Great work Simon! ❤️