Allow overriding skipping/scaling with custom AudioProcessors

Issue: #3142

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=193519029

RELEASENOTES.md

@@ -53,6 +53,8 @@
     with encoder padding when the decoder returns a non-empty final buffer.
     with encoder padding when the decoder returns a non-empty final buffer.
   * Allow trimming more than one sample when applying an elst audio edit via
   * Allow trimming more than one sample when applying an elst audio edit via
     gapless playback info.
     gapless playback info.
+  * Allow overriding skipping/scaling with custom `AudioProcessor`s
+    ((#3142)[https://github.com/google/ExoPlayer/issues/3142]).
 * Caching:
 * Caching:
   * Add release method to Cache interface.
   * Add release method to Cache interface.
   * Prevent multiple instances of SimpleCache in the same folder.
   * Prevent multiple instances of SimpleCache in the same folder.

library/core/src/main/java/com/google/android/exoplayer2/audio/SilenceSkippingAudioProcessor.java

@@ -27,7 +27,7 @@ import java.nio.ByteOrder;
  * An {@link AudioProcessor} that skips silence in the input stream. Input and output are 16-bit
  * An {@link AudioProcessor} that skips silence in the input stream. Input and output are 16-bit
  * PCM.
  * PCM.
  */
  */
-/* package */ final class SilenceSkippingAudioProcessor implements AudioProcessor {
+public final class SilenceSkippingAudioProcessor implements AudioProcessor {
 
 
   /**
   /**
    * The minimum duration of audio that must be below {@link #SILENCE_THRESHOLD_LEVEL} to classify
    * The minimum duration of audio that must be below {@link #SILENCE_THRESHOLD_LEVEL} to classify