[webvtt] Pull Request: Region lines cannot be negative now that they are unsigned long.

silviapfeiffer has just submitted a new pull request for https://github.com/w3c/webvtt:

== Region lines cannot be negative now that they are unsigned long. ==
Closes #414

See https://github.com/w3c/webvtt/pull/423

Received on Friday, 22 December 2017 14:29:59 UTC