SDK / exoplayer

Issue: #791

Issue: #789

There is no guarantee codec names start with this prefix in >= L.

Issue: #782

It can do weird things if the device has an unusual default Locale.
Util.toLowerInvariant uses the US Locale, which does the right thing
in this case.

- Allow a moof box to exceed the search size.
- Return immediately after reading an ftyp box with no compatible types.

Issue: #784

Partial fix for #778

This allows the demo app to display subtitles without video
(when there's no video, the shutter view does not hide itself).

When switching format in HLS, we instantiate a new extractor, which
adjusts TS presentation timestamps so that they align properly with
the start of the first segment in the new format. Some HLS streams
appear to have slightly misalignment that causes a glitch when using
this approach.

It's better to re-use the same timestamp adjustment across formats,
and only reset it when seeking or when there's an actual discontinuity.
This is because the HLS spec guarantees PTS timestamp alignment across
different formats.

We'll also need something like PtsTimestampAdjuster to share between
separated audio and WebVTT tracks, which also contain PTS timestamps
that are aligned, and will need to share a common adjustment.

Issue: #692

- Don't allow "nothing has changed" optimization in the case
  that only styling has changed (TextUtils.equals will return
  true in this case, but we shouldn't optimize).
- Add functionality to suppress embedded styling; seems useful
  to have.
- Added "this." for clarity.

Issue: #764

Issue: #707

Issue: #771

When a live stream ends, what typically happens is that the manifest
is refreshed and the refreshed version is not marked as live/dynamic.
When this happens we:

1. Don't want the duration of the track to change.
2. Still want to consider the possibility that we may have fallen behind
   the live window.
3. Don't want to allow futher manifest refreshes.

This change uses the right thing in the right place.

Issue: #707

Ignore extra returns in Subrip parsing

Issue #765

Issue #763

Issue: #755

- Admit we don't know the mime type (using unknown mime types) rather
  than passing the container mime type.
- Pass the correct mime type for opus, vp9 and vp8, and remove the incorrect
  container checks in the corresponding extensions.

All valid Android devices should pass these tests.

- Fix building with APP_ABI=all by configuring for all architectures.
- Keep vpx_dsp which is required for building successfully.
- Use perl -pi -e not sed, for building on Macs.

Issue #753

- With this change, you can select from the individual video formats in
the demo app, as well as the regular "auto" (adaptive) track.
- DashRendererBuilder no longer needs to create MultiTrackChunkSource
instances for the multiple tracks to be exposed.