Legacy players, e.g. older versions of ExoPlayer, do not handle default webvtt text alignment correctly. Need to specify `align:center` explicitly cues without text alignment for backwards compatibility.
Fixes#925.
The test added in the previous CL was broken due to a rebase on another
change. This subtly changed some of the byte offsets that broke the
test. This wasn't caught since I didn't rebase and re-run the tests
before merging.
Change-Id: Id7e4c7688278eae37da1a14f1648263b4dda98cd
This changes it from an OriginHandler to a MediaParser and moves the
handling of it to the Demuxer. This will allow more generic handling
of text by giving it the same abstractions as video/audio handling.
Change-Id: Ibbde3c84d228ec8e83af1ed266ea97dbc9589c24