SDK / exoplayer

For DASH + SS, sample data is currently plumbed through:

Extractor
->ChunkExtractorWrapper
->ContainerMediaChunk
->DefaultTrackOutput
->RollingSampleNBuffer

This change bypasses the ContainerMediaChunk layer. It
should be possible to completely delete DefaultTrackOutput
in the future, but such a change may well be tied to
changes in HLS format splicing + how we buffer (or don't
buffer) disabled tracks.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=119853857