Re-enable codec re-use

Issue: #2826

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219130576

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

@@ -536,6 +536,16 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
   @Override
   protected void onDisabled() {
     inputFormat = null;
+    if (drmSession != null || pendingDrmSession != null) {
+      // TODO: Do something better with this case.
+      onReset();
+    } else {
+      flushOrReleaseCodec();
+    }
+  }
+
+  @Override
+  protected void onReset() {
     try {
       releaseCodec();
     } finally {
@@ -559,14 +569,14 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
   protected void releaseCodec() {
     availableCodecInfos = null;
     if (codec != null) {
+      codecInfo = null;
+      codecFormat = null;
       resetInputBuffer();
       resetOutputBuffer();
       resetCodecBuffers();
-      codecHotswapDeadlineMs = C.TIME_UNSET;
       waitingForKeys = false;
+      codecHotswapDeadlineMs = C.TIME_UNSET;
       decodeOnlyPresentationTimestamps.clear();
-      codecInfo = null;
-      codecFormat = null;
       decoderCounters.decoderReleaseCount++;
       try {
         codec.stop();

library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java

@@ -283,8 +283,12 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
   @Override
   protected void onEnabled(boolean joining) throws ExoPlaybackException {
     super.onEnabled(joining);
+    int oldTunnelingAudioSessionId = tunnelingAudioSessionId;
     tunnelingAudioSessionId = getConfiguration().tunnelingAudioSessionId;
     tunneling = tunnelingAudioSessionId != C.AUDIO_SESSION_ID_UNSET;
+    if (tunnelingAudioSessionId != oldTunnelingAudioSessionId) {
+      releaseCodec();
+    }
     eventDispatcher.enabled(decoderCounters);
     frameReleaseTimeHelper.enable();
   }