[whatwg] Full screen for the <video> element

[Ivo Emanuel Gonçalves]

As far as I understand this issue, the best solution is to leave it up
to the user-agent.  If they want to provide a full screen option let
them have it.  If users find it annoying or if it's heavily abused,
they either disable it or move to another browser that knows what it's
doing(tm).

Basically, full screen video should be a client thing.  The HTML 5
spec should merely suggest user-agents not to start in full screen
mode by default.  I think that's a good compromise.  Not elegant, but
probably works.

-Ivo