SDK / exoplayer

Previously the SonicAudioProcessor and SilenceSkippingAudioProcessor would track
their pending playback parameters and only apply them in flush(). Having the
values only take effect once flushed made the processors a bit more difficult to
use, especially because the value returned by isActive wouldn't update
immediately.

Make DefaultAudioSink only set the new speed/pitch/skip silence setting after
the audio processors have drained. This means it's no longer necessary to keep
track of pending parameter values and also fixes a bug where initial playback
parameters weren't applied because the audio processors weren't flushed while
uninitialized before DefaultAudioSink called isActive() on them.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=191586727