Exclude TrackGroup fields/methods from the stable API

App code should get all of this information from TrackGroupInfo,
and should only need TrackGroup as a key to use for overrides.

PiperOrigin-RevId: 438840925

libraries/common/src/main/java/androidx/media3/common/TrackGroup.java

@@ -54,11 +54,11 @@ public final class TrackGroup implements Bundleable {
   private static final String TAG = "TrackGroup";
 
   /** The number of tracks in the group. */
-  public final int length;
+  @UnstableApi public final int length;
   /** An identifier for the track group. */
-  public final String id;
+  @UnstableApi public final String id;
   /** The type of tracks in the group. */
-  public final @C.TrackType int type;
+  @UnstableApi public final @C.TrackType int type;
 
   private final Format[] formats;
 
@@ -113,6 +113,7 @@ public final class TrackGroup implements Bundleable {
    * @param index The index of the track.
    * @return The track's format.
    */
+  @UnstableApi
   public Format getFormat(int index) {
     return formats[index];
   }
@@ -126,6 +127,7 @@ public final class TrackGroup implements Bundleable {
    * @return The index of the track, or {@link C#INDEX_UNSET} if no such track exists.
    */
   @SuppressWarnings("ReferenceEquality")
+  @UnstableApi
   public int indexOf(Format format) {
     for (int i = 0; i < formats.length; i++) {
       if (format == formats[i]) {

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/EventLogger.java

@@ -31,7 +31,6 @@ import androidx.media3.common.PlaybackParameters;
 import androidx.media3.common.Player;
 import androidx.media3.common.Player.PlaybackSuppressionReason;
 import androidx.media3.common.Timeline;
-import androidx.media3.common.TrackGroup;
 import androidx.media3.common.TracksInfo;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.util.Log;
@@ -288,11 +287,10 @@ public class EventLogger implements AnalyticsListener {
     // Log metadata for at most one of the selected tracks.
     boolean loggedMetadata = false;
     for (int groupIndex = 0; !loggedMetadata && groupIndex < trackGroupInfos.size(); groupIndex++) {
-      TracksInfo.TrackGroupInfo trackGroupInfo = trackGroupInfos.get(groupIndex);
-      TrackGroup trackGroup = trackGroupInfo.getTrackGroup();
+      TracksInfo.TrackGroupInfo trackGroup = trackGroupInfos.get(groupIndex);
       for (int trackIndex = 0; !loggedMetadata && trackIndex < trackGroup.length; trackIndex++) {
-        if (trackGroupInfo.isTrackSelected(trackIndex)) {
-          @Nullable Metadata metadata = trackGroup.getFormat(trackIndex).metadata;
+        if (trackGroup.isTrackSelected(trackIndex)) {
+          @Nullable Metadata metadata = trackGroup.getTrackFormat(trackIndex).metadata;
           if (metadata != null && metadata.length() > 0) {
             logd("  Metadata [");
             printMetadata(metadata, "    ");