Timestamp data types and HTMLMediaElement currentTime

[chrisn]

Feedback from @paulhiggs in #40:

Also, by using DOMTimeStamp (instead of unsigned long long) will we ever run into problems with the HTMLMediaElement attributes...

// playback state
         attribute double currentTime;
readonly attribute unrestricted double duration;

especially when it comes to recording something from the current point in the Media Element?

[chrisn]

DOMTimeStamp is a typedef for unsigned long long, so I don't believe this change in itself will cause a problem. But, in addition to the impedance mismatch issue, it also raises the interesting question of how we establish the media timeline for a media element connected to a TVMediaStream.