Following up with the changes made in http://dev.w3.org/html5/webvtt/#dfn-dom-vttcue-vertical, this patch comes to create a new enum to validate and control the possible values for TextTrackCue::Vertical. Throwing behavior was removed for spec conformance.
This way we can ensure that JS code written for WebVTT is spec
compliant while at the same time not having to abstract VTTCue
from TextTrackCue.
--HG--
rename : dom/webidl/TextTrackCue.webidl => dom/webidl/VTTCue.webidl
