[ttml2] Add missing xml:base attribute.

skynavga has just created a new issue for https://github.com/w3c/ttml2:

== Add missing xml:base attribute. ==
The ``xml:base`` attribute is missing from the following elements that employ a possibly relative ``<uri>`` valued attribute, e.g., ``src`` and ``xlink:href``:
- ``audio``
- ``data``
- ``font``
- ``image``
- ``span``
- ``source``

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/804 using your GitHub account

Received on Tuesday, 29 May 2018 02:40:31 UTC