This change introduces handlers to output WebVtt text files. There is
only one output but there is a common base to support others.
WebVttOutputHandler which handles all communication with other handlers
and WebVttSegmentedOutputHandler is responsible for listening for events
and choosing when and where to write cues and headers.
Bug: 36138902
Change-Id: I2b13a94262554398e66fee8cf024aa21041ddbab
To ensure that the style data is formatted correctly, changing the
set_style method to AppendStyle so that joining values will be
done in controlled setting.
Change-Id: Ia88e2d260b11339e6777ff018813e8aeb802a501
Added a text sample type that can be passed between media handlers.
This will allow text samples to safely be moved between media
handlers before converting to their final format.
Bug: 36138902
Change-Id: Ic4946f774a7d37c43066b9ea46596d5c5f3c05a8