[ttml2] Pull Request: Add #length-root-container-relative feature (#718).

skynavga has just submitted a new pull request for https://github.com/w3c/ttml2:

== Add #length-root-container-relative feature (#718). ==
Closes #718.

See https://github.com/w3c/ttml2/pull/739

Received on Saturday, 12 May 2018 19:02:29 UTC