Decode and encode audio in TransformerAudioRenderer.

There is no speed adjustment or use of sonic, as that will
come in a child CL.

PiperOrigin-RevId: 351973892

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/SynchronousMediaCodecAdapter.java

@@ -34,7 +34,7 @@ import java.nio.ByteBuffer;
 /**
  * A {@link MediaCodecAdapter} that operates the underlying {@link MediaCodec} in synchronous mode.
  */
-/* package */ final class SynchronousMediaCodecAdapter implements MediaCodecAdapter {
+public final class SynchronousMediaCodecAdapter implements MediaCodecAdapter {
 
   /** A factory for {@link SynchronousMediaCodecAdapter} instances. */
   public static final class Factory implements MediaCodecAdapter.Factory {