[css3-mediaqueries][css-device-adapt] Combining @viewport with the Fullscreen API

[Kenneth Rohde Christiansen]

In order for CSS Device Adaptation and Fullscreen to work better
together and work with orientation lock in fullscreen mode, I suggest
(idea by Rune) we extend the view-mode media feature with the below
syntax. I also suggest that we move the view-mode media feature into
Media Queries Level 4.

@media all and (view-mode: fullscreen(#element1)) {
    @viewport {
        orientation: portrait;
    }
}

@media all and (view-mode: fullscreen(#element2)) {
    @viewport {
        orientation: landscape;
    }
}

This way a page can have multiple fullscreen enabled elements which
each their viewport configuration which will be applied when they
enter fullscreen.

Cheers
Kenneth