SDK / exoplayer

- This moves to a single DrmInitData implementation that supports
  both specific and universal UUID matching. You can also do a
  combination of the two, which was not previously possible.
- The object model is simplified as a result. This is a precursor
  to a change where DrmInitData will be included directly in the
  Format to enable key rotation.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=121472592