Use single TrackGroup for switchable adaptation sets

Issue: #2431

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=157236031

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashChunkSource.java

@@ -28,8 +28,8 @@ public interface DashChunkSource extends ChunkSource {
   interface Factory {
 
     DashChunkSource createDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
-        DashManifest manifest, int periodIndex, int adaptationSetIndex,
-        TrackSelection trackSelection, long elapsedRealtimeOffsetMs,
+        DashManifest manifest, int periodIndex, int[] adaptationSetIndices,
+        TrackSelection trackSelection, int type, long elapsedRealtimeOffsetMs,
         boolean enableEventMessageTrack, boolean enableCea608Track);
 
   }

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DefaultDashChunkSource.java

@@ -46,6 +46,7 @@ import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -69,20 +70,21 @@ public class DefaultDashChunkSource implements DashChunkSource {
 
     @Override
     public DashChunkSource createDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
-        DashManifest manifest, int periodIndex, int adaptationSetIndex,
-        TrackSelection trackSelection, long elapsedRealtimeOffsetMs,
+        DashManifest manifest, int periodIndex, int[] adaptationSetIndices,
+        TrackSelection trackSelection, int trackType, long elapsedRealtimeOffsetMs,
         boolean enableEventMessageTrack, boolean enableCea608Track) {
       DataSource dataSource = dataSourceFactory.createDataSource();
       return new DefaultDashChunkSource(manifestLoaderErrorThrower, manifest, periodIndex,
-          adaptationSetIndex, trackSelection, dataSource, elapsedRealtimeOffsetMs,
+          adaptationSetIndices, trackSelection, trackType, dataSource, elapsedRealtimeOffsetMs,
           maxSegmentsPerLoad, enableEventMessageTrack, enableCea608Track);
     }
 
   }
 
   private final LoaderErrorThrower manifestLoaderErrorThrower;
-  private final int adaptationSetIndex;
+  private final int[] adaptationSetIndices;
   private final TrackSelection trackSelection;
+  private final int trackType;
   private final RepresentationHolder[] representationHolders;
   private final DataSource dataSource;
   private final long elapsedRealtimeOffsetMs;
@@ -98,8 +100,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
    * @param manifestLoaderErrorThrower Throws errors affecting loading of manifests.
    * @param manifest The initial manifest.
    * @param periodIndex The index of the period in the manifest.
-   * @param adaptationSetIndex The index of the adaptation set in the period.
+   * @param adaptationSetIndices The indices of the adaptation sets in the period.
    * @param trackSelection The track selection.
+   * @param trackType The type of the tracks in the selection.
    * @param dataSource A {@link DataSource} suitable for loading the media data.
    * @param elapsedRealtimeOffsetMs If known, an estimate of the instantaneous difference between
    *     server-side unix time and {@link SystemClock#elapsedRealtime()} in milliseconds, specified
@@ -112,26 +115,27 @@ public class DefaultDashChunkSource implements DashChunkSource {
    * @param enableCea608Track Whether the chunks generated by the source may output a CEA-608 track.
    */
   public DefaultDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
-      DashManifest manifest, int periodIndex, int adaptationSetIndex, TrackSelection trackSelection,
-      DataSource dataSource, long elapsedRealtimeOffsetMs, int maxSegmentsPerLoad,
-      boolean enableEventMessageTrack, boolean enableCea608Track) {
+      DashManifest manifest, int periodIndex, int[] adaptationSetIndices,
+      TrackSelection trackSelection, int trackType, DataSource dataSource,
+      long elapsedRealtimeOffsetMs, int maxSegmentsPerLoad, boolean enableEventMessageTrack,
+      boolean enableCea608Track) {
     this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
     this.manifest = manifest;
-    this.adaptationSetIndex = adaptationSetIndex;
+    this.adaptationSetIndices = adaptationSetIndices;
     this.trackSelection = trackSelection;
+    this.trackType = trackType;
     this.dataSource = dataSource;
     this.periodIndex = periodIndex;
     this.elapsedRealtimeOffsetMs = elapsedRealtimeOffsetMs;
     this.maxSegmentsPerLoad = maxSegmentsPerLoad;
 
     long periodDurationUs = manifest.getPeriodDurationUs(periodIndex);
-    AdaptationSet adaptationSet = getAdaptationSet();
-    List<Representation> representations = adaptationSet.representations;
+    List<Representation> representations = getRepresentations();
     representationHolders = new RepresentationHolder[trackSelection.length()];
     for (int i = 0; i < representationHolders.length; i++) {
       Representation representation = representations.get(trackSelection.getIndexInTrackGroup(i));
       representationHolders[i] = new RepresentationHolder(periodDurationUs, representation,
-          enableEventMessageTrack, enableCea608Track, adaptationSet.type);
+          enableEventMessageTrack, enableCea608Track);
     }
   }
 
@@ -141,7 +145,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
       manifest = newManifest;
       periodIndex = newPeriodIndex;
       long periodDurationUs = manifest.getPeriodDurationUs(periodIndex);
-      List<Representation> representations = getAdaptationSet().representations;
+      List<Representation> representations = getRepresentations();
       for (int i = 0; i < representationHolders.length; i++) {
         Representation representation = representations.get(trackSelection.getIndexInTrackGroup(i));
         representationHolders[i].updateRepresentation(periodDurationUs, representation);
@@ -248,9 +252,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
     }
 
     int maxSegmentCount = Math.min(maxSegmentsPerLoad, lastAvailableSegmentNum - segmentNum + 1);
-    out.chunk = newMediaChunk(representationHolder, dataSource, trackSelection.getSelectedFormat(),
-        trackSelection.getSelectionReason(), trackSelection.getSelectionData(), segmentNum,
-        maxSegmentCount);
+    out.chunk = newMediaChunk(representationHolder, dataSource, trackType,
+        trackSelection.getSelectedFormat(), trackSelection.getSelectionReason(),
+        trackSelection.getSelectionData(), segmentNum, maxSegmentCount);
   }
 
   @Override
@@ -298,8 +302,13 @@ public class DefaultDashChunkSource implements DashChunkSource {
 
   // Private methods.
 
-  private AdaptationSet getAdaptationSet() {
-    return manifest.getPeriod(periodIndex).adaptationSets.get(adaptationSetIndex);
+  private ArrayList<Representation> getRepresentations() {
+    List<AdaptationSet> manifestAdapationSets = manifest.getPeriod(periodIndex).adaptationSets;
+    ArrayList<Representation> representations = new ArrayList<>();
+    for (int adaptationSetIndex : adaptationSetIndices) {
+      representations.addAll(manifestAdapationSets.get(adaptationSetIndex).representations);
+    }
+    return representations;
   }
 
   private long getNowUnixTimeUs() {
@@ -332,7 +341,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
   }
 
   private static Chunk newMediaChunk(RepresentationHolder representationHolder,
-      DataSource dataSource, Format trackFormat, int trackSelectionReason,
+      DataSource dataSource, int trackType, Format trackFormat, int trackSelectionReason,
       Object trackSelectionData, int firstSegmentNum, int maxSegmentCount) {
     Representation representation = representationHolder.representation;
     long startTimeUs = representationHolder.getSegmentStartTimeUs(firstSegmentNum);
@@ -343,8 +352,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
       DataSpec dataSpec = new DataSpec(segmentUri.resolveUri(baseUrl),
           segmentUri.start, segmentUri.length, representation.getCacheKey());
       return new SingleSampleMediaChunk(dataSource, dataSpec, trackFormat, trackSelectionReason,
-          trackSelectionData, startTimeUs, endTimeUs, firstSegmentNum,
-          representationHolder.trackType, trackFormat);
+          trackSelectionData, startTimeUs, endTimeUs, firstSegmentNum, trackType, trackFormat);
     } else {
       int segmentCount = 1;
       for (int i = 1; i < maxSegmentCount; i++) {
@@ -371,7 +379,6 @@ public class DefaultDashChunkSource implements DashChunkSource {
 
   protected static final class RepresentationHolder {
 
-    public final int trackType;
     public final ChunkExtractorWrapper extractorWrapper;
 
     public Representation representation;
@@ -381,10 +388,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
     private int segmentNumShift;
 
     public RepresentationHolder(long periodDurationUs, Representation representation,
-        boolean enableEventMessageTrack, boolean enableCea608Track, int trackType) {
+        boolean enableEventMessageTrack, boolean enableCea608Track) {
       this.periodDurationUs = periodDurationUs;
       this.representation = representation;
-      this.trackType = trackType;
       String containerMimeType = representation.format.containerMimeType;
       if (mimeTypeIsRawText(containerMimeType)) {
         extractorWrapper = null;