- Don't report errors to listeners if playback will immediately
fail. Doing so is redundant, since such errors are immediately
reported through ExoPlayer's listener as a result of playback
failure. We were also reporting these errors inconsistently
across renderers.
- Reduce code duplication through EventDispatcher classes.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=122519976
