HLS: use video duration instead of using text duration

[kqyang]

NOTE: For bugs, if you delete this template, we will send it again and ask you to fill it out.

Have you read the FAQ and checked for duplicate open issues?:

Yes.

What version of Shaka Player are you using?:

Latest public demo.

Can you reproduce the issue with our latest release version?:

Yes.

Can you reproduce the issue with the latest code from master?:

Yes.

Are you using the demo app or your own custom app?:

Demo app.

If custom app, can you reproduce the issue using our demo app?:

What browser and OS are you using?:

Chrome on Linux.

What are the manifest and license server URIs?:
(NOTE: you can send the URIs to shaka-player-issues@google.com instead, but please use GitHub and the template for the rest)
(NOTE: a copy of the manifest text or an attached manifest will not be enough to reproduce your issue, and we will ask you to send a URI instead)

https://storage.googleapis.com/wvtemp/kqyang/vtt6/bunny_vtt_master.m3u8

What did you do?

https://shaka-player-demo.appspot.com/demo/#asset=https://storage.googleapis.com/wvtemp/kqyang/vtt6/bunny_vtt_master.m3u8;lang=en-US;build=uncompiled

What did you expect to happen?

Total duration should be around 60 seconds. See the equivalent manifest in DASH, which is handled properly: https://shaka-player-demo.appspot.com/demo/#asset=https://storage.googleapis.com/wvtemp/kqyang/vtt6/bunny.mpd;lang=en-US;build=uncompiled.

What actually happened?

The total duration is about 10 seconds, which is based on the text duration.

v2.1.9 seems to work.

[TheModMaker]

Yep, looks like a bug. Should be easy to fix, we just need to ignore text tracks when calculating the min stream duration.

[joeyparrish]

Cherry-picked for v2.3.3.