This is called when reaching end of the file of the media. The duration
of the media is updated.
Fixes#340.
Change-Id: I446f2d341b02125d4a7d8c958bda269b5403cb9c
Created end-to-end tests for the segmented webvtt text in HLS. The
text stream is longer than both audio and video, so there are more
text segments than video/audio.
Change-Id: Ib860ccd3f2ac0048983fdeebe3847a0b9dcbc160