SDK / exoplayer

- Remove null checks (never happens).
- Use "const".equals(Util.CONST) where possible.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128351654

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128345063

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128190311

The classes these tests are written for have changed
so much we'll have to write them again. We can refer
to V1 if we want to look at what the old tests did, so
there's no need to keep this file in the V2 tree at
the moment.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128189076

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128160177

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128159118

- TrackSelection now exposes the selected formats, ordered
  by decreasing bandwidth. This removes the need for DASH,
  SS and HLS to do the sorting individually.
- The change also removes the need to reconstruct TrackSelection
  instances with a different group index in various places
  (e.g. MergingMediaPeriod).
- This is also a step toward potentially packaging the
  FormatEvaluator inside of the TrackSelection (TBD).

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128159064

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Created by MOE: https://github.com/google/moe
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128082468

According to the spec, there is no mandatory relation between segments'
sequence numbers of different variants. This CL ignores sequence numbers
when switching variants:

* In vod, the switching playback position is obtained by adding the
    duration of previous segments.
* In live playback this is not possible. It is assumed that the
    different live media playlists do not drift apart too much, so
    the playback position is obtained by subtracting the duration
    in reverse order.

In later CLs, the described mechanisms will become the fallback methods
by replacing them with the use of EXT-X-PROGRAM-DATE-TIME information
or more reliable sources.

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Created by MOE: https://github.com/google/moe
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ISSUE: #1681

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Created by MOE: https://github.com/google/moe
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128060676

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128045581

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Created by MOE: https://github.com/google/moe
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Created by MOE: https://github.com/google/moe
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It's the only place that uses it.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127927164

SmoothStreaming -> Ss
MediaPresentationDescription -> DashManifest
DashSingleSegmentIndex -> SingleSegmentIndex

Moved DASH and Ss manifest classes to matching
manifest packages for consistency. For Hls the
package is called playlist still, since that's
what they're widely known as.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127925961

This also removes direct use of HttpURLConnection and
allows use of any HttpDataSource for license requests,
which means those using OkHttp can finally use the
same network stack for license requests as they're using
for everything else, without having to implement their
own callback.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127841045

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Created by MOE: https://github.com/google/moe
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Issue: #548

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127821150

With this change, MediaCodecRenderer acquires a session
from its DrmSessionManager whenever the DrmInitData in
the format changes. The DrmSessionManager is permitted
to return the same session if it can be re-used.

This plumbing adds support for:

1. Key-rotation, in the case that a key-rotation-aware
   DrmSessionManager is used. Such an implementation will
   return the same DrmSession for every aquisition, but
   will be making use of multiple MediaDrm instances within
   that session to enable the rotation.

2. Playlists with mixed clear and protected content. One
   final piece to this will be to have each MediaPeriod
   provide its own license URL. We could also allow each
   MediaPeriod to specify the DRM UUID, but switching from
   PlayReady to Widevine in a playlist seems like quite a
   hypothetical thing.

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Created by MOE: https://github.com/google/moe
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127811486

This is a no-op change to avoid an error-prone unnecessary
boolean expression warning.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127787709

There may be other ways to estimate bandwidth that don't
require listening to our own transfers.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127741651

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Created by MOE: https://github.com/google/moe
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This was possible previously, but now we support things
like multi-period DASH we need to do the injection in
the form of factories rather than concrete instances.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127735816

- Cleaned up documentation
- Removed getIndex from Renderer interface
- Renamed reset to be positionReset

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127731006

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127551577

This change restores ExoPlayer to its previous behaviour.
I think we'll want a "resetPosition" boolean parameter on
setMediaSource at some point, but no need to add it right
now. Note that this would not always reset to the start
of the source. For a live playback it will reset to the
desired position (normally somewhere slightly behind the
live edge).

Issue: #1667
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Created by MOE: https://github.com/google/moe
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127536151

Renderer no longer extends RendererCapabilities after this
change. Capabilities are instead accessed via a getter.
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MOE_MIGRATED_REVID=127532634

In V1 we received complaints that Renderer was too locked down.
In particular, it wasn't possible to implement a Renderer that
wrapped another Renderer, since most of the methods were package
private and final (e.g. enable).

This change defines Renderer as a proper interface, removing
this limitation. A method-reordering-only change will follow
this one, to get things into a nice consistent/sane order in
each of the Renderer classes.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127527995

We should only give a TrackSelector access to what it
needs, not the whole Renderer. This is particular true
if [] happens, since more Renderer methods
will become publicly visible.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127526473

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127441130

DashMediaPeriod.releasePeriod resets duration to 0, but
instances are currently being re-used through multiple
prepare/release cycles. Hence the duration needs to be
retained. This change fixes this issue, and also makes
variables final in DashMediaPeriod where possible.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127440080

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127436600

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127415273

1. Rename "extensions" package to "decoder". It's used by both
   text and (should be used by) metadata, so it's no longer just
   for extensions.
2. Move Buffer objects move into the decoder package.
3. Rename SubtitleParser and MetadataParser to SubtitleDecoder
   and MetadataDecoder respectively, since they extend Decoder.
   Ditto for all subclasses.
4. Subtitle and Metadata decoders now throw their own exception
   types rather than ParserException.
5. Move MediaCodec classes into a mediacodec package, with the
   exception of the concrete audio and video renderers.
6. Create an audio package to hold the two audio renderer classes
   plus related util classes.
7. Create a video package to hold the one video renderer class
   plus related util classes.

After this change the following nice properties hold:

1. Want a video renderer? Look in the video package. Ditto for
   audio, text and metadata.
2. All TrackRenderer implementations use a decoder of some kind
   to decode buffers received from the source, so we have
   consistent terminology there.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127326805

The BandwidthMeter should only be used by MediaSource
instances and the objects they reference, so there's
really no reason for the player to need to know about it.

This change sacrifices DebugTextViewHelper showing the
estimated bandwidth, but I think that's a price worth
paying.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127316755

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127315877