I'm looking into adding support for WebVTT embedded in Matroska (MKV).

I managed to get basic support in this patch: https://github.com/moneytoo/ExoPlayer/commit/09b07da83fb9cf6a0a6e511e7c0f6282c963e1da and it seems to be working with the sample provided to me in here: moneytoo/Player#249

The patch still lacks support for styles as described in Matroska specs. I'm planning on looking into the styles as well, but I'm pretty busy lately so I'm wondering if I should send you PR with this basic support (is it worth an attempt?) or better wait and finish it all?