Make id3 context usage robust against container format changes

Issue:#3622

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=182363243

RELEASENOTES.md

@@ -2,8 +2,6 @@
 
 ### dev-v2 (not yet released) ###
 
-* HLS: Fix mime type propagation
-  ([#3653](https://github.com/google/ExoPlayer/issues/3653)).
 * SimpleExoPlayerView: Automatically apply video rotation if
   `SimpleExoPlayerView` is configured to use `TextureView`
   ([#91](https://github.com/google/ExoPlayer/issues/91)).
@@ -50,6 +48,10 @@
       significantly reduce initial buffering time
       ([#3149](https://github.com/google/ExoPlayer/issues/3149)).
     * Fail on loss of sync with Transport Stream.
+    * Fix mime type propagation
+      ([#3653](https://github.com/google/ExoPlayer/issues/3653)).
+    * Fix ID3 context reuse across segment format changes
+      ([#3622](https://github.com/google/ExoPlayer/issues/3622)).
 * New Cast extension: Simplifies toggling between local and Cast playbacks.
 * Audio: Support TrueHD passthrough for rechunked samples in Matroska files
   ([#2147](https://github.com/google/ExoPlayer/issues/2147)).

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaChunk.java

@@ -137,9 +137,13 @@ import java.util.concurrent.atomic.AtomicInteger;
     reusingExtractor = extractor == previousExtractor;
     initLoadCompleted = reusingExtractor && initDataSpec != null;
     if (isPackedAudioExtractor) {
-      id3Decoder = previousChunk != null ? previousChunk.id3Decoder : new Id3Decoder();
-      id3Data =  previousChunk != null ? previousChunk.id3Data
-          : new ParsableByteArray(Id3Decoder.ID3_HEADER_LENGTH);
+      if (previousChunk != null && previousChunk.id3Data != null) {
+        id3Decoder = previousChunk.id3Decoder;
+        id3Data = previousChunk.id3Data;
+      } else {
+        id3Decoder = new Id3Decoder();
+        id3Data = new ParsableByteArray(Id3Decoder.ID3_HEADER_LENGTH);
+      }
     } else {
       id3Decoder = null;
       id3Data = null;