Handle non-empty EoS buffers, for audio

This fixes gapless playback of streams with encoder padding on devices where the
decoder could set the end of stream flag on a non-empty final buffer.

Issue: #3449

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=192407924

RELEASENOTES.md

@@ -41,6 +41,8 @@
   * Fix an issue where playback of TrueHD streams would get stuck after seeking
   * Fix an issue where playback of TrueHD streams would get stuck after seeking
     due to not finding a syncframe
     due to not finding a syncframe
     ((#3845)[https://github.com/google/ExoPlayer/issues/3845]).
     ((#3845)[https://github.com/google/ExoPlayer/issues/3845]).
+  * Handle non-empty end-of-stream buffers, to fix gapless playback of streams
+    with encoder padding when the decoder returns a non-empty final buffer.
 * 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/mediacodec/MediaCodecRenderer.java

@@ -1027,7 +1027,8 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
           shouldSkipAdaptationWorkaroundOutputBuffer = false;
           shouldSkipAdaptationWorkaroundOutputBuffer = false;
           codec.releaseOutputBuffer(outputIndex, false);
           codec.releaseOutputBuffer(outputIndex, false);
           return true;
           return true;
-        } else if ((outputBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
+        } else if (outputBufferInfo.size == 0
+            && (outputBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
           // The dequeued buffer indicates the end of the stream. Process it immediately.
           // The dequeued buffer indicates the end of the stream. Process it immediately.
           processEndOfStream();
           processEndOfStream();
           return false;
           return false;
@@ -1094,8 +1095,12 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
 
 
     if (processedOutputBuffer) {
     if (processedOutputBuffer) {
       onProcessedOutputBuffer(outputBufferInfo.presentationTimeUs);
       onProcessedOutputBuffer(outputBufferInfo.presentationTimeUs);
+      boolean isEndOfStream = (outputBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0;
       resetOutputBuffer();
       resetOutputBuffer();
-      return true;
+      if (!isEndOfStream) {
+        return true;
+      }
+      processEndOfStream();
     }
     }
 
 
     return false;
     return false;