Remove generic type parameter from TransferListener.

All known instances use DataSource as generic type and thus code can be simplified
by removing the generic type altogether.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=205798542

extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java

@@ -22,7 +22,6 @@ import android.util.Log;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.upstream.BaseDataSource;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSourceException;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
@@ -163,7 +162,7 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
       CronetEngine cronetEngine,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener) {
+      @Nullable TransferListener listener) {
     this(cronetEngine, executor, contentTypePredicate, listener, DEFAULT_CONNECT_TIMEOUT_MILLIS,
         DEFAULT_READ_TIMEOUT_MILLIS, false, null, false);
   }
@@ -188,7 +187,7 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
       CronetEngine cronetEngine,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMs,
       int readTimeoutMs,
       boolean resetTimeoutOnRedirects,
@@ -219,7 +218,7 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
       CronetEngine cronetEngine,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMs,
       int readTimeoutMs,
       boolean resetTimeoutOnRedirects,
@@ -234,7 +233,7 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
       CronetEngine cronetEngine,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMs,
       int readTimeoutMs,
       boolean resetTimeoutOnRedirects,

extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSourceFactory.java

@@ -16,7 +16,6 @@
 package com.google.android.exoplayer2.ext.cronet;
 
 import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DefaultHttpDataSourceFactory;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource.BaseFactory;
@@ -47,7 +46,7 @@ public final class CronetDataSourceFactory extends BaseFactory {
   private final CronetEngineWrapper cronetEngineWrapper;
   private final Executor executor;
   private final Predicate<String> contentTypePredicate;
-  private final @Nullable TransferListener<? super DataSource> transferListener;
+  private final @Nullable TransferListener transferListener;
   private final int connectTimeoutMs;
   private final int readTimeoutMs;
   private final boolean resetTimeoutOnRedirects;
@@ -224,7 +223,7 @@ public final class CronetDataSourceFactory extends BaseFactory {
       CronetEngineWrapper cronetEngineWrapper,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       HttpDataSource.Factory fallbackFactory) {
     this(cronetEngineWrapper, executor, contentTypePredicate, transferListener,
         DEFAULT_CONNECT_TIMEOUT_MILLIS, DEFAULT_READ_TIMEOUT_MILLIS, false, fallbackFactory);
@@ -252,7 +251,7 @@ public final class CronetDataSourceFactory extends BaseFactory {
       CronetEngineWrapper cronetEngineWrapper,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       String userAgent) {
     this(cronetEngineWrapper, executor, contentTypePredicate, transferListener,
         DEFAULT_CONNECT_TIMEOUT_MILLIS, DEFAULT_READ_TIMEOUT_MILLIS, false,
@@ -281,7 +280,7 @@ public final class CronetDataSourceFactory extends BaseFactory {
       CronetEngineWrapper cronetEngineWrapper,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       int connectTimeoutMs,
       int readTimeoutMs,
       boolean resetTimeoutOnRedirects,
@@ -314,7 +313,7 @@ public final class CronetDataSourceFactory extends BaseFactory {
       CronetEngineWrapper cronetEngineWrapper,
       Executor executor,
       Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       int connectTimeoutMs,
       int readTimeoutMs,
       boolean resetTimeoutOnRedirects,

extensions/cronet/src/test/java/com/google/android/exoplayer2/ext/cronet/CronetDataSourceTest.java

@@ -32,7 +32,6 @@ import android.net.Uri;
 import android.os.ConditionVariable;
 import android.os.SystemClock;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource.HttpDataSourceException;
@@ -87,7 +86,7 @@ public final class CronetDataSourceTest {
   @Mock private UrlRequest.Builder mockUrlRequestBuilder;
   @Mock private UrlRequest mockUrlRequest;
   @Mock private Predicate<String> mockContentTypePredicate;
-  @Mock private TransferListener<DataSource> mockTransferListener;
+  @Mock private TransferListener mockTransferListener;
   @Mock private Executor mockExecutor;
   @Mock private NetworkException mockNetworkException;
   @Mock private CronetEngine mockCronetEngine;

extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsMediaSource.java

@@ -80,7 +80,7 @@ public final class ImaAdsMediaSource extends BaseMediaSource implements SourceIn
   public void prepareSourceInternal(
       final ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     adsMediaSource.prepareSource(
         player, isTopLevelSource, /* listener= */ this, mediaTransferListener);
   }

extensions/okhttp/src/main/java/com/google/android/exoplayer2/ext/okhttp/OkHttpDataSource.java

@@ -21,7 +21,6 @@ import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.upstream.BaseDataSource;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSourceException;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
@@ -97,7 +96,7 @@ public class OkHttpDataSource extends BaseDataSource implements HttpDataSource {
       @NonNull Call.Factory callFactory,
       @Nullable String userAgent,
       @Nullable Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener) {
+      @Nullable TransferListener listener) {
     this(callFactory, userAgent, contentTypePredicate, listener, null, null);
   }
 
@@ -117,7 +116,7 @@ public class OkHttpDataSource extends BaseDataSource implements HttpDataSource {
       @NonNull Call.Factory callFactory,
       @Nullable String userAgent,
       @Nullable Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       @Nullable CacheControl cacheControl,
       @Nullable RequestProperties defaultRequestProperties) {
     super(/* isNetwork= */ true);

extensions/okhttp/src/main/java/com/google/android/exoplayer2/ext/okhttp/OkHttpDataSourceFactory.java

@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.ext.okhttp;
 
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource;
 import com.google.android.exoplayer2.upstream.HttpDataSource.BaseFactory;
 import com.google.android.exoplayer2.upstream.HttpDataSource.Factory;
@@ -32,7 +31,7 @@ public final class OkHttpDataSourceFactory extends BaseFactory {
 
   @NonNull private final Call.Factory callFactory;
   @Nullable private final String userAgent;
-  @Nullable private final TransferListener<? super DataSource> listener;
+  @Nullable private final TransferListener listener;
   @Nullable private final CacheControl cacheControl;
 
   /**
@@ -63,8 +62,10 @@ public final class OkHttpDataSourceFactory extends BaseFactory {
    * @param userAgent An optional User-Agent string.
    * @param listener An optional listener.
    */
-  public OkHttpDataSourceFactory(@NonNull Call.Factory callFactory, @Nullable String userAgent,
+  public OkHttpDataSourceFactory(
-      @Nullable TransferListener<? super DataSource> listener) {
+      @NonNull Call.Factory callFactory,
+      @Nullable String userAgent,
+      @Nullable TransferListener listener) {
     this(callFactory, userAgent, listener, /* cacheControl= */ null);
   }
 
@@ -75,8 +76,10 @@ public final class OkHttpDataSourceFactory extends BaseFactory {
    * @param listener An optional listener.
    * @param cacheControl An optional {@link CacheControl} for setting the Cache-Control header.
    */
-  public OkHttpDataSourceFactory(@NonNull Call.Factory callFactory, @Nullable String userAgent,
+  public OkHttpDataSourceFactory(
-      @Nullable TransferListener<? super DataSource> listener,
+      @NonNull Call.Factory callFactory,
+      @Nullable String userAgent,
+      @Nullable TransferListener listener,
       @Nullable CacheControl cacheControl) {
     this.callFactory = callFactory;
     this.userAgent = userAgent;

extensions/rtmp/src/main/java/com/google/android/exoplayer2/ext/rtmp/RtmpDataSource.java

@@ -42,7 +42,7 @@ public final class RtmpDataSource extends BaseDataSource {
   }
 
   /** @param listener An optional listener. */
-  public RtmpDataSource(@Nullable TransferListener<? super DataSource> listener) {
+  public RtmpDataSource(@Nullable TransferListener listener) {
     super(/* isNetwork= */ true);
     if (listener != null) {
       addTransferListener(listener);

extensions/rtmp/src/main/java/com/google/android/exoplayer2/ext/rtmp/RtmpDataSourceFactory.java

@@ -25,14 +25,14 @@ import com.google.android.exoplayer2.upstream.TransferListener;
  */
 public final class RtmpDataSourceFactory implements DataSource.Factory {
 
-  private final @Nullable TransferListener<? super DataSource> listener;
+  private final @Nullable TransferListener listener;
 
   public RtmpDataSourceFactory() {
     this(null);
   }
 
   /** @param listener An optional listener. */
-  public RtmpDataSourceFactory(@Nullable TransferListener<? super DataSource> listener) {
+  public RtmpDataSourceFactory(@Nullable TransferListener listener) {
     this.listener = listener;
   }
 

library/core/src/main/java/com/google/android/exoplayer2/source/BaseMediaSource.java

@@ -19,7 +19,6 @@ import android.os.Handler;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.ArrayList;
@@ -59,9 +58,7 @@ public abstract class BaseMediaSource implements MediaSource {
    *     manifests and other data.
    */
   protected abstract void prepareSourceInternal(
-      ExoPlayer player,
+      ExoPlayer player, boolean isTopLevelSource, @Nullable TransferListener mediaTransferListener);
-      boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener);
 
   /**
    * Releases the source. This method is called exactly once after each call to {@link
@@ -147,7 +144,7 @@ public abstract class BaseMediaSource implements MediaSource {
       ExoPlayer player,
       boolean isTopLevelSource,
       SourceInfoRefreshListener listener,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     Assertions.checkArgument(this.player == null || this.player == player);
     sourceInfoListeners.add(listener);
     if (this.player == null) {

library/core/src/main/java/com/google/android/exoplayer2/source/ClippingMediaSource.java

@@ -21,7 +21,6 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
@@ -216,7 +215,7 @@ public final class ClippingMediaSource extends CompositeMediaSource<Void> {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
     prepareChildSource(/* id= */ null, mediaSource);
   }

library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java

@@ -20,7 +20,6 @@ import android.support.annotation.CallSuper;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
@@ -38,7 +37,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
 
   private @Nullable ExoPlayer player;
   private @Nullable Handler eventHandler;
-  private @Nullable TransferListener<? super DataSource> mediaTransferListener;
+  private @Nullable TransferListener mediaTransferListener;
 
   /** Create composite media source without child sources. */
   protected CompositeMediaSource() {
@@ -50,7 +49,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     this.player = player;
     this.mediaTransferListener = mediaTransferListener;
     eventHandler = new Handler();

library/core/src/main/java/com/google/android/exoplayer2/source/ConcatenatingMediaSource.java

@@ -26,7 +26,6 @@ import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource.MediaSourceHolder;
 import com.google.android.exoplayer2.source.ShuffleOrder.DefaultShuffleOrder;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
@@ -376,7 +375,7 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
   public final synchronized void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
     this.player = player;
     playerApplicationHandler = new Handler(player.getApplicationLooper());

library/core/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaSource.java

@@ -241,7 +241,7 @@ public final class ExtractorMediaSource extends BaseMediaSource
 
   private long timelineDurationUs;
   private boolean timelineIsSeekable;
-  private @Nullable TransferListener<? super DataSource> transferListener;
+  private @Nullable TransferListener transferListener;
 
   /**
    * @param uri The {@link Uri} of the media stream.
@@ -347,7 +347,7 @@ public final class ExtractorMediaSource extends BaseMediaSource
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     transferListener = mediaTransferListener;
     notifySourceInfoRefreshed(timelineDurationUs, /* isSeekable= */ false);
   }

library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java

@@ -22,7 +22,6 @@ import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.source.ShuffleOrder.UnshuffledShuffleOrder;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 
@@ -65,7 +64,7 @@ public final class LoopingMediaSource extends CompositeMediaSource<Void> {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
     prepareChildSource(/* id= */ null, childSource);
   }

library/core/src/main/java/com/google/android/exoplayer2/source/MediaSource.java

@@ -21,7 +21,6 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 
@@ -257,7 +256,7 @@ public interface MediaSource {
       ExoPlayer player,
       boolean isTopLevelSource,
       SourceInfoRefreshListener listener,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener);
+      @Nullable TransferListener mediaTransferListener);
 
   /**
    * Throws any pending error encountered while loading or refreshing source information.

library/core/src/main/java/com/google/android/exoplayer2/source/MergingMediaSource.java

@@ -20,7 +20,6 @@ import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 import java.lang.annotation.Retention;
@@ -102,7 +101,7 @@ public final class MergingMediaSource extends CompositeMediaSource<Integer> {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
     for (int i = 0; i < mediaSources.length; i++) {
       prepareChildSource(i, mediaSources[i]);

library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaPeriod.java

@@ -49,7 +49,7 @@ import java.util.Arrays;
 
   private final DataSpec dataSpec;
   private final DataSource.Factory dataSourceFactory;
-  private final @Nullable TransferListener<? super DataSource> transferListener;
+  private final @Nullable TransferListener transferListener;
   private final int minLoadableRetryCount;
   private final EventDispatcher eventDispatcher;
   private final TrackGroupArray tracks;
@@ -70,7 +70,7 @@ import java.util.Arrays;
   public SingleSampleMediaPeriod(
       DataSpec dataSpec,
       DataSource.Factory dataSourceFactory,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       Format format,
       long durationUs,
       int minLoadableRetryCount,

library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java

@@ -169,7 +169,7 @@ public final class SingleSampleMediaSource extends BaseMediaSource {
   private final boolean treatLoadErrorsAsEndOfStream;
   private final Timeline timeline;
 
-  private @Nullable TransferListener<? super DataSource> transferListener;
+  private @Nullable TransferListener transferListener;
 
   /**
    * @param uri The {@link Uri} of the media stream.
@@ -274,7 +274,7 @@ public final class SingleSampleMediaSource extends BaseMediaSource {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     transferListener = mediaTransferListener;
     refreshSourceInfo(timeline, /* manifest= */ null);
   }

library/core/src/main/java/com/google/android/exoplayer2/source/ads/AdsMediaSource.java

@@ -309,7 +309,7 @@ public final class AdsMediaSource extends CompositeMediaSource<MediaPeriodId> {
   public void prepareSourceInternal(
       final ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
     Assertions.checkArgument(isTopLevelSource);
     final ComponentListener componentListener = new ComponentListener();

library/core/src/main/java/com/google/android/exoplayer2/upstream/AssetDataSource.java

@@ -56,7 +56,7 @@ public final class AssetDataSource extends BaseDataSource {
    * @param context A context.
    * @param listener An optional listener.
    */
-  public AssetDataSource(Context context, @Nullable TransferListener<? super DataSource> listener) {
+  public AssetDataSource(Context context, @Nullable TransferListener listener) {
     super(/* isNetwork= */ false);
     this.assetManager = context.getAssets();
     if (listener != null) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/BandwidthMeter.java

@@ -49,7 +49,7 @@ public interface BandwidthMeter {
    * from data transfers. May be null, if no transfer listener is used.
    */
   @Nullable
-  TransferListener<? super DataSource> getTransferListener();
+  TransferListener getTransferListener();
 
   /**
    * Adds an {@link EventListener} to be informed of bandwidth samples.

library/core/src/main/java/com/google/android/exoplayer2/upstream/BaseDataSource.java

@@ -29,7 +29,7 @@ import java.util.ArrayList;
 public abstract class BaseDataSource implements DataSource {
 
   private final boolean isNetwork;
-  private final ArrayList<TransferListener<? super DataSource>> listeners;
+  private final ArrayList<TransferListener> listeners;
 
   private @Nullable DataSpec dataSpec;
 
@@ -44,7 +44,7 @@ public abstract class BaseDataSource implements DataSource {
   }
 
   @Override
-  public final void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public final void addTransferListener(TransferListener transferListener) {
     listeners.add(transferListener);
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/ContentDataSource.java

@@ -60,8 +60,7 @@ public final class ContentDataSource extends BaseDataSource {
    * @param context A context.
    * @param listener An optional listener.
    */
-  public ContentDataSource(
+  public ContentDataSource(Context context, @Nullable TransferListener listener) {
-      Context context, @Nullable TransferListener<? super DataSource> listener) {
     super(/* isNetwork= */ false);
     this.resolver = context.getContentResolver();
     if (listener != null) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSource.java

@@ -44,7 +44,7 @@ public interface DataSource {
    *
    * @param transferListener A {@link TransferListener}.
    */
-  default void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  default void addTransferListener(TransferListener transferListener) {
     // TODO: Make non-default once all DataSources implement this method.
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultBandwidthMeter.java

@@ -26,7 +26,7 @@ import com.google.android.exoplayer2.util.SlidingPercentile;
  * Estimates bandwidth by listening to data transfers. The bandwidth estimate is calculated using a
  * {@link SlidingPercentile} and is updated each time a transfer ends.
  */
-public final class DefaultBandwidthMeter implements BandwidthMeter, TransferListener<Object> {
+public final class DefaultBandwidthMeter implements BandwidthMeter, TransferListener {
 
   /** Default initial bitrate estimate in bits per second. */
   public static final long DEFAULT_INITIAL_BITRATE_ESTIMATE = 1_000_000;
@@ -169,7 +169,7 @@ public final class DefaultBandwidthMeter implements BandwidthMeter, TransferList
   }
 
   @Override
-  public @Nullable TransferListener<? super DataSource> getTransferListener() {
+  public @Nullable TransferListener getTransferListener() {
     return this;
   }
 
@@ -184,12 +184,13 @@ public final class DefaultBandwidthMeter implements BandwidthMeter, TransferList
   }
 
   @Override
-  public void onTransferInitializing(Object source, DataSpec dataSpec, boolean isNetwork) {
+  public void onTransferInitializing(DataSource source, DataSpec dataSpec, boolean isNetwork) {
     // Do nothing.
   }
 
   @Override
-  public synchronized void onTransferStart(Object source, DataSpec dataSpec, boolean isNetwork) {
+  public synchronized void onTransferStart(
+      DataSource source, DataSpec dataSpec, boolean isNetwork) {
     if (!isNetwork) {
       return;
     }
@@ -201,7 +202,7 @@ public final class DefaultBandwidthMeter implements BandwidthMeter, TransferList
 
   @Override
   public synchronized void onBytesTransferred(
-      Object source, DataSpec dataSpec, boolean isNetwork, int bytes) {
+      DataSource source, DataSpec dataSpec, boolean isNetwork, int bytes) {
     if (!isNetwork) {
       return;
     }
@@ -209,7 +210,7 @@ public final class DefaultBandwidthMeter implements BandwidthMeter, TransferList
   }
 
   @Override
-  public synchronized void onTransferEnd(Object source, DataSpec dataSpec, boolean isNetwork) {
+  public synchronized void onTransferEnd(DataSource source, DataSpec dataSpec, boolean isNetwork) {
     if (!isNetwork) {
       return;
     }

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultDataSource.java

@@ -57,7 +57,7 @@ public final class DefaultDataSource implements DataSource {
   private static final String SCHEME_RAW = RawResourceDataSource.RAW_RESOURCE_SCHEME;
 
   private final Context context;
-  private final List<TransferListener<? super DataSource>> transferListeners;
+  private final List<TransferListener> transferListeners;
   private final DataSource baseDataSource;
 
   // Lazily initialized.
@@ -81,7 +81,7 @@ public final class DefaultDataSource implements DataSource {
    */
   public DefaultDataSource(
       Context context,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       String userAgent,
       boolean allowCrossProtocolRedirects) {
     this(context, listener, userAgent, DefaultHttpDataSource.DEFAULT_CONNECT_TIMEOUT_MILLIS,
@@ -103,7 +103,7 @@ public final class DefaultDataSource implements DataSource {
    */
   public DefaultDataSource(
       Context context,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       String userAgent,
       int connectTimeoutMillis,
       int readTimeoutMillis,
@@ -123,9 +123,7 @@ public final class DefaultDataSource implements DataSource {
    *     content. This {@link DataSource} should normally support at least http(s).
    */
   public DefaultDataSource(
-      Context context,
+      Context context, @Nullable TransferListener listener, DataSource baseDataSource) {
-      @Nullable TransferListener<? super DataSource> listener,
-      DataSource baseDataSource) {
     this.context = context.getApplicationContext();
     this.baseDataSource = Assertions.checkNotNull(baseDataSource);
     transferListeners = new ArrayList<>();
@@ -135,7 +133,7 @@ public final class DefaultDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     baseDataSource.addTransferListener(transferListener);
     transferListeners.add(transferListener);
     maybeAddListenerToDataSource(fileDataSource, transferListener);
@@ -271,7 +269,7 @@ public final class DefaultDataSource implements DataSource {
   }
 
   private void maybeAddListenerToDataSource(
-      @Nullable DataSource dataSource, TransferListener<? super DataSource> listener) {
+      @Nullable DataSource dataSource, TransferListener listener) {
     if (dataSource != null) {
       dataSource.addTransferListener(listener);
     }

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultDataSourceFactory.java

@@ -26,7 +26,7 @@ import com.google.android.exoplayer2.upstream.DataSource.Factory;
 public final class DefaultDataSourceFactory implements Factory {
 
   private final Context context;
-  private final @Nullable TransferListener<? super DataSource> listener;
+  private final @Nullable TransferListener listener;
   private final DataSource.Factory baseDataSourceFactory;
 
   /**
@@ -43,7 +43,7 @@ public final class DefaultDataSourceFactory implements Factory {
    * @param listener An optional listener.
    */
   public DefaultDataSourceFactory(
-      Context context, String userAgent, @Nullable TransferListener<? super DataSource> listener) {
+      Context context, String userAgent, @Nullable TransferListener listener) {
     this(context, listener, new DefaultHttpDataSourceFactory(userAgent, listener));
   }
 
@@ -66,7 +66,7 @@ public final class DefaultDataSourceFactory implements Factory {
    */
   public DefaultDataSourceFactory(
       Context context,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       DataSource.Factory baseDataSourceFactory) {
     this.context = context.getApplicationContext();
     this.listener = listener;

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSource.java

@@ -105,7 +105,7 @@ public class DefaultHttpDataSource extends BaseDataSource implements HttpDataSou
   public DefaultHttpDataSource(
       String userAgent,
       @Nullable Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener) {
+      @Nullable TransferListener listener) {
     this(userAgent, contentTypePredicate, listener, DEFAULT_CONNECT_TIMEOUT_MILLIS,
         DEFAULT_READ_TIMEOUT_MILLIS);
   }
@@ -124,7 +124,7 @@ public class DefaultHttpDataSource extends BaseDataSource implements HttpDataSou
   public DefaultHttpDataSource(
       String userAgent,
       @Nullable Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMillis,
       int readTimeoutMillis) {
     this(userAgent, contentTypePredicate, listener, connectTimeoutMillis, readTimeoutMillis, false,
@@ -150,7 +150,7 @@ public class DefaultHttpDataSource extends BaseDataSource implements HttpDataSou
   public DefaultHttpDataSource(
       String userAgent,
       @Nullable Predicate<String> contentTypePredicate,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMillis,
       int readTimeoutMillis,
       boolean allowCrossProtocolRedirects,

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSourceFactory.java

@@ -23,7 +23,7 @@ import com.google.android.exoplayer2.upstream.HttpDataSource.Factory;
 public final class DefaultHttpDataSourceFactory extends BaseFactory {
 
   private final String userAgent;
-  private final @Nullable TransferListener<? super DataSource> listener;
+  private final @Nullable TransferListener listener;
   private final int connectTimeoutMillis;
   private final int readTimeoutMillis;
   private final boolean allowCrossProtocolRedirects;
@@ -50,8 +50,7 @@ public final class DefaultHttpDataSourceFactory extends BaseFactory {
    * @param listener An optional listener.
    * @see #DefaultHttpDataSourceFactory(String, TransferListener, int, int, boolean)
    */
-  public DefaultHttpDataSourceFactory(
+  public DefaultHttpDataSourceFactory(String userAgent, @Nullable TransferListener listener) {
-      String userAgent, @Nullable TransferListener<? super DataSource> listener) {
     this(userAgent, listener, DefaultHttpDataSource.DEFAULT_CONNECT_TIMEOUT_MILLIS,
         DefaultHttpDataSource.DEFAULT_READ_TIMEOUT_MILLIS, false);
   }
@@ -90,7 +89,7 @@ public final class DefaultHttpDataSourceFactory extends BaseFactory {
    */
   public DefaultHttpDataSourceFactory(
       String userAgent,
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener,
       int connectTimeoutMillis,
       int readTimeoutMillis,
       boolean allowCrossProtocolRedirects) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/FileDataSource.java

@@ -46,7 +46,7 @@ public final class FileDataSource extends BaseDataSource {
   }
 
   /** @param listener An optional listener. */
-  public FileDataSource(@Nullable TransferListener<? super DataSource> listener) {
+  public FileDataSource(@Nullable TransferListener listener) {
     super(/* isNetwork= */ false);
     if (listener != null) {
       addTransferListener(listener);

library/core/src/main/java/com/google/android/exoplayer2/upstream/FileDataSourceFactory.java

@@ -22,13 +22,13 @@ import android.support.annotation.Nullable;
  */
 public final class FileDataSourceFactory implements DataSource.Factory {
 
-  private final @Nullable TransferListener<? super DataSource> listener;
+  private final @Nullable TransferListener listener;
 
   public FileDataSourceFactory() {
     this(null);
   }
 
-  public FileDataSourceFactory(@Nullable TransferListener<? super DataSource> listener) {
+  public FileDataSourceFactory(@Nullable TransferListener listener) {
     this.listener = listener;
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/PriorityDataSource.java

@@ -54,7 +54,7 @@ public final class PriorityDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     upstream.addTransferListener(transferListener);
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/RawResourceDataSource.java

@@ -81,8 +81,7 @@ public final class RawResourceDataSource extends BaseDataSource {
    * @param context A context.
    * @param listener An optional listener.
    */
-  public RawResourceDataSource(
+  public RawResourceDataSource(Context context, @Nullable TransferListener listener) {
-      Context context, @Nullable TransferListener<? super DataSource> listener) {
     super(/* isNetwork= */ false);
     this.resources = context.getResources();
     if (listener != null) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/StatsDataSource.java

@@ -71,7 +71,7 @@ public final class StatsDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     dataSource.addTransferListener(transferListener);
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/TeeDataSource.java

@@ -44,7 +44,7 @@ public final class TeeDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     upstream.addTransferListener(transferListener);
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/TransferListener.java

@@ -22,20 +22,20 @@ package com.google.android.exoplayer2.upstream;
  *
  * <ol>
  *   <li>Initializing the underlying resource (e.g. opening a HTTP connection). {@link
- *       #onTransferInitializing(Object, DataSpec, boolean)} is called before the initialization
+ *       #onTransferInitializing(DataSource, DataSpec, boolean)} is called before the initialization
  *       starts.
  *   <li>Starting the transfer after successfully initializing the resource. {@link
- *       #onTransferStart(Object, DataSpec, boolean)} is called. Note that this only happens if the
+ *       #onTransferStart(DataSource, DataSpec, boolean)} is called. Note that this only happens if
- *       initialization was successful.
+ *       the initialization was successful.
- *   <li>Transferring data. {@link #onBytesTransferred(Object, DataSpec, boolean, int)} is called
+ *   <li>Transferring data. {@link #onBytesTransferred(DataSource, DataSpec, boolean, int)} is
- *       frequently during the transfer to indicate progress.
+ *       called frequently during the transfer to indicate progress.
- *   <li>Closing the transfer and the underlying resource. {@link #onTransferEnd(Object, DataSpec,
+ *   <li>Closing the transfer and the underlying resource. {@link #onTransferEnd(DataSource,
- *       boolean)} is called. Note that each {@link #onTransferStart(Object, DataSpec, boolean)}
+ *       DataSpec, boolean)} is called. Note that each {@link #onTransferStart(DataSource, DataSpec,
- *       will have exactly one corresponding call to {@link #onTransferEnd(Object, DataSpec,
+ *       boolean)} will have exactly one corresponding call to {@link #onTransferEnd(DataSource,
- *       boolean)}.
+ *       DataSpec, boolean)}.
  * </ol>
  */
-public interface TransferListener<S> {
+public interface TransferListener {
 
   /**
    * Called when a transfer is being initialized.
@@ -44,7 +44,7 @@ public interface TransferListener<S> {
    * @param dataSpec Describes the data for which the transfer is initialized.
    * @param isNetwork Whether the data is transferred through a network.
    */
-  void onTransferInitializing(S source, DataSpec dataSpec, boolean isNetwork);
+  void onTransferInitializing(DataSource source, DataSpec dataSpec, boolean isNetwork);
 
   /**
    * Called when a transfer starts.
@@ -53,7 +53,7 @@ public interface TransferListener<S> {
    * @param dataSpec Describes the data being transferred.
    * @param isNetwork Whether the data is transferred through a network.
    */
-  void onTransferStart(S source, DataSpec dataSpec, boolean isNetwork);
+  void onTransferStart(DataSource source, DataSpec dataSpec, boolean isNetwork);
 
   /**
    * Called incrementally during a transfer.
@@ -63,7 +63,8 @@ public interface TransferListener<S> {
    * @param isNetwork Whether the data is transferred through a network.
    * @param bytesTransferred The number of bytes transferred since the previous call to this method
    */
-  void onBytesTransferred(S source, DataSpec dataSpec, boolean isNetwork, int bytesTransferred);
+  void onBytesTransferred(
+      DataSource source, DataSpec dataSpec, boolean isNetwork, int bytesTransferred);
 
   /**
    * Called when a transfer ends.
@@ -72,5 +73,5 @@ public interface TransferListener<S> {
    * @param dataSpec Describes the data being transferred.
    * @param isNetwork Whether the data is transferred through a network.
    */
-  void onTransferEnd(S source, DataSpec dataSpec, boolean isNetwork);
+  void onTransferEnd(DataSource source, DataSpec dataSpec, boolean isNetwork);
 }

library/core/src/main/java/com/google/android/exoplayer2/upstream/UdpDataSource.java

@@ -64,7 +64,7 @@ public final class UdpDataSource extends BaseDataSource {
   private int packetRemaining;
 
   /** @param listener An optional listener. */
-  public UdpDataSource(@Nullable TransferListener<? super DataSource> listener) {
+  public UdpDataSource(@Nullable TransferListener listener) {
     this(listener, DEFAULT_MAX_PACKET_SIZE);
   }
 
@@ -72,7 +72,7 @@ public final class UdpDataSource extends BaseDataSource {
    * @param listener An optional listener.
    * @param maxPacketSize The maximum datagram packet size, in bytes.
    */
-  public UdpDataSource(@Nullable TransferListener<? super DataSource> listener, int maxPacketSize) {
+  public UdpDataSource(@Nullable TransferListener listener, int maxPacketSize) {
     this(listener, maxPacketSize, DEAFULT_SOCKET_TIMEOUT_MILLIS);
   }
 
@@ -83,9 +83,7 @@ public final class UdpDataSource extends BaseDataSource {
    *     as an infinite timeout.
    */
   public UdpDataSource(
-      @Nullable TransferListener<? super DataSource> listener,
+      @Nullable TransferListener listener, int maxPacketSize, int socketTimeoutMillis) {
-      int maxPacketSize,
-      int socketTimeoutMillis) {
     super(/* isNetwork= */ true);
     this.socketTimeoutMillis = socketTimeoutMillis;
     packetBuffer = new byte[maxPacketSize];

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java

@@ -258,7 +258,7 @@ public final class CacheDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     cacheReadDataSource.addTransferListener(transferListener);
     upstreamDataSource.addTransferListener(transferListener);
   }

library/core/src/main/java/com/google/android/exoplayer2/upstream/crypto/AesCipherDataSource.java

@@ -42,7 +42,7 @@ public final class AesCipherDataSource implements DataSource {
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     upstream.addTransferListener(transferListener);
   }
 

library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java

@@ -45,7 +45,6 @@ import com.google.android.exoplayer2.testutil.FakeTrackSelection;
 import com.google.android.exoplayer2.testutil.FakeTrackSelector;
 import com.google.android.exoplayer2.testutil.RobolectricUtil;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -234,7 +233,7 @@ public final class ExoPlayerTest {
           public synchronized void prepareSourceInternal(
               ExoPlayer player,
               boolean isTopLevelSource,
-              @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+              @Nullable TransferListener mediaTransferListener) {
             super.prepareSourceInternal(player, isTopLevelSource, mediaTransferListener);
             // We've queued a source info refresh on the playback thread's event queue. Allow the
             // test thread to prepare the player with the third source, and block this thread (the
@@ -582,7 +581,7 @@ public final class ExoPlayerTest {
               TrackGroupArray trackGroupArray,
               Allocator allocator,
               EventDispatcher eventDispatcher,
-              @Nullable TransferListener<? super DataSource> transferListener) {
+              @Nullable TransferListener transferListener) {
             FakeMediaPeriod mediaPeriod = new FakeMediaPeriod(trackGroupArray, eventDispatcher);
             mediaPeriod.setSeekToUsOffset(10);
             return mediaPeriod;
@@ -617,7 +616,7 @@ public final class ExoPlayerTest {
               TrackGroupArray trackGroupArray,
               Allocator allocator,
               EventDispatcher eventDispatcher,
-              @Nullable TransferListener<? super DataSource> transferListener) {
+              @Nullable TransferListener transferListener) {
             FakeMediaPeriod mediaPeriod = new FakeMediaPeriod(trackGroupArray, eventDispatcher);
             mediaPeriod.setDiscontinuityPositionUs(10);
             return mediaPeriod;
@@ -643,7 +642,7 @@ public final class ExoPlayerTest {
               TrackGroupArray trackGroupArray,
               Allocator allocator,
               EventDispatcher eventDispatcher,
-              @Nullable TransferListener<? super DataSource> transferListener) {
+              @Nullable TransferListener transferListener) {
             FakeMediaPeriod mediaPeriod = new FakeMediaPeriod(trackGroupArray, eventDispatcher);
             mediaPeriod.setDiscontinuityPositionUs(0);
             return mediaPeriod;
@@ -880,7 +879,7 @@ public final class ExoPlayerTest {
               TrackGroupArray trackGroupArray,
               Allocator allocator,
               EventDispatcher eventDispatcher,
-              @Nullable TransferListener<? super DataSource> transferListener) {
+              @Nullable TransferListener transferListener) {
             // Defer completing preparation of the period until playback parameters have been set.
             fakeMediaPeriodHolder[0] =
                 new FakeMediaPeriod(trackGroupArray, eventDispatcher, /* deferOnPrepared= */ true);

library/core/src/test/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java

@@ -37,7 +37,6 @@ import com.google.android.exoplayer2.testutil.MediaSourceTestRunner;
 import com.google.android.exoplayer2.testutil.RobolectricUtil;
 import com.google.android.exoplayer2.testutil.TimelineAsserts;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 import org.junit.Before;
@@ -481,7 +480,7 @@ public final class ClippingMediaSourceTest {
               TrackGroupArray trackGroupArray,
               Allocator allocator,
               EventDispatcher eventDispatcher,
-              @Nullable TransferListener<? super DataSource> transferListener) {
+              @Nullable TransferListener transferListener) {
             eventDispatcher.downstreamFormatChanged(
                 new MediaLoadData(
                     C.DATA_TYPE_MEDIA,

library/core/src/test/java/com/google/android/exoplayer2/upstream/BaseDataSourceTest.java

@@ -117,7 +117,7 @@ public class BaseDataSourceTest {
     }
   }
 
-  private static final class TestTransferListener implements TransferListener<DataSource> {
+  private static final class TestTransferListener implements TransferListener {
 
     public Object lastTransferInitializingSource;
     public DataSpec lastTransferInitializingDataSpec;

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

@@ -21,7 +21,6 @@ import com.google.android.exoplayer2.source.chunk.ChunkSource;
 import com.google.android.exoplayer2.source.dash.PlayerEmsgHandler.PlayerTrackEmsgHandler;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
 
@@ -61,7 +60,7 @@ public interface DashChunkSource extends ChunkSource {
         boolean enableEventMessageTrack,
         boolean enableCea608Track,
         @Nullable PlayerTrackEmsgHandler playerEmsgHandler,
-        @Nullable TransferListener<? super DataSource> transferListener);
+        @Nullable TransferListener transferListener);
   }
 
   /**

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

@@ -42,7 +42,6 @@ import com.google.android.exoplayer2.source.dash.manifest.Period;
 import com.google.android.exoplayer2.source.dash.manifest.Representation;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.MimeTypes;
@@ -62,7 +61,7 @@ import java.util.List;
 
   /* package */ final int id;
   private final DashChunkSource.Factory chunkSourceFactory;
-  private final @Nullable TransferListener<? super DataSource> transferListener;
+  private final @Nullable TransferListener transferListener;
   private final int minLoadableRetryCount;
   private final long elapsedRealtimeOffset;
   private final LoaderErrorThrower manifestLoaderErrorThrower;
@@ -89,7 +88,7 @@ import java.util.List;
       DashManifest manifest,
       int periodIndex,
       DashChunkSource.Factory chunkSourceFactory,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       int minLoadableRetryCount,
       EventDispatcher eventDispatcher,
       long elapsedRealtimeOffset,

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

@@ -344,7 +344,7 @@ public final class DashMediaSource extends BaseMediaSource {
 
   private DataSource dataSource;
   private Loader loader;
-  private @Nullable TransferListener<? super DataSource> mediaTransferListener;
+  private @Nullable TransferListener mediaTransferListener;
 
   private IOException manifestFatalError;
   private Handler handler;
@@ -596,7 +596,7 @@ public final class DashMediaSource extends BaseMediaSource {
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     if (sideloadedManifest) {
       processManifest(false);

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

@@ -89,7 +89,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
         boolean enableEventMessageTrack,
         boolean enableCea608Track,
         @Nullable PlayerTrackEmsgHandler playerEmsgHandler,
-        @Nullable TransferListener<? super DataSource> transferListener) {
+        @Nullable TransferListener transferListener) {
       DataSource dataSource = dataSourceFactory.createDataSource();
       if (transferListener != null) {
         dataSource.addTransferListener(transferListener);

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/Aes128DataSource.java

@@ -65,7 +65,7 @@ import javax.crypto.spec.SecretKeySpec;
   }
 
   @Override
-  public void addTransferListener(TransferListener<? super DataSource> transferListener) {
+  public void addTransferListener(TransferListener transferListener) {
     upstream.addTransferListener(transferListener);
   }
 

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

@@ -129,7 +129,7 @@ import java.util.List;
       HlsPlaylistTracker playlistTracker,
       HlsUrl[] variants,
       HlsDataSourceFactory dataSourceFactory,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener,
+      @Nullable TransferListener mediaTransferListener,
       TimestampAdjusterProvider timestampAdjusterProvider,
       List<Format> muxedCaptionFormats) {
     this.extractorFactory = extractorFactory;

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

@@ -55,7 +55,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
   private final HlsExtractorFactory extractorFactory;
   private final HlsPlaylistTracker playlistTracker;
   private final HlsDataSourceFactory dataSourceFactory;
-  private final @Nullable TransferListener<? super DataSource> mediaTransferListener;
+  private final @Nullable TransferListener mediaTransferListener;
   private final LoadErrorHandlingPolicy<Chunk> chunkLoadErrorHandlingPolicy;
   private final int minLoadableRetryCount;
   private final EventDispatcher eventDispatcher;
@@ -94,7 +94,7 @@ public final class HlsMediaPeriod implements MediaPeriod, HlsSampleStreamWrapper
       HlsExtractorFactory extractorFactory,
       HlsPlaylistTracker playlistTracker,
       HlsDataSourceFactory dataSourceFactory,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener,
+      @Nullable TransferListener mediaTransferListener,
       LoadErrorHandlingPolicy<Chunk> chunkLoadErrorHandlingPolicy,
       int minLoadableRetryCount,
       EventDispatcher eventDispatcher,

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

@@ -287,7 +287,7 @@ public final class HlsMediaSource extends BaseMediaSource
   private final HlsPlaylistTracker playlistTracker;
   private final @Nullable Object tag;
 
-  private @Nullable TransferListener<? super DataSource> mediaTransferListener;
+  private @Nullable TransferListener mediaTransferListener;
 
   /**
    * @param manifestUri The {@link Uri} of the HLS manifest.
@@ -402,7 +402,7 @@ public final class HlsMediaSource extends BaseMediaSource
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     EventDispatcher eventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
     playlistTracker.start(manifestUri, eventDispatcher, /* listener= */ this);

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/DefaultSsChunkSource.java

@@ -61,7 +61,7 @@ public class DefaultSsChunkSource implements SsChunkSource {
         int elementIndex,
         TrackSelection trackSelection,
         TrackEncryptionBox[] trackEncryptionBoxes,
-        @Nullable TransferListener<? super DataSource> transferListener) {
+        @Nullable TransferListener transferListener) {
       DataSource dataSource = dataSourceFactory.createDataSource();
       if (transferListener != null) {
         dataSource.addTransferListener(transferListener);

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsChunkSource.java

@@ -20,7 +20,6 @@ import com.google.android.exoplayer2.extractor.mp4.TrackEncryptionBox;
 import com.google.android.exoplayer2.source.chunk.ChunkSource;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
 
@@ -50,7 +49,7 @@ public interface SsChunkSource extends ChunkSource {
         int streamElementIndex,
         TrackSelection trackSelection,
         TrackEncryptionBox[] trackEncryptionBoxes,
-        @Nullable TransferListener<? super DataSource> transferListener);
+        @Nullable TransferListener transferListener);
   }
 
   /**

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriod.java

@@ -32,7 +32,6 @@ import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest.ProtectionElement;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
@@ -47,7 +46,7 @@ import java.util.ArrayList;
   private static final int INITIALIZATION_VECTOR_SIZE = 8;
 
   private final SsChunkSource.Factory chunkSourceFactory;
-  private final @Nullable TransferListener<? super DataSource> transferListener;
+  private final @Nullable TransferListener transferListener;
   private final LoaderErrorThrower manifestLoaderErrorThrower;
   private final int minLoadableRetryCount;
   private final EventDispatcher eventDispatcher;
@@ -65,7 +64,7 @@ import java.util.ArrayList;
   public SsMediaPeriod(
       SsManifest manifest,
       SsChunkSource.Factory chunkSourceFactory,
-      @Nullable TransferListener<? super DataSource> transferListener,
+      @Nullable TransferListener transferListener,
       CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory,
       int minLoadableRetryCount,
       EventDispatcher eventDispatcher,

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java

@@ -295,7 +295,7 @@ public final class SsMediaSource extends BaseMediaSource
   private DataSource manifestDataSource;
   private Loader manifestLoader;
   private LoaderErrorThrower manifestLoaderErrorThrower;
-  private @Nullable TransferListener<? super DataSource> mediaTransferListener;
+  private @Nullable TransferListener mediaTransferListener;
 
   private long manifestLoadStartTimestamp;
   private SsManifest manifest;
@@ -477,7 +477,7 @@ public final class SsMediaSource extends BaseMediaSource
   public void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     if (sideloadedManifest) {
       manifestLoaderErrorThrower = new LoaderErrorThrower.Dummy();

playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/DashTestRunner.java

@@ -307,8 +307,8 @@ public final class DashTestRunner {
     }
 
     @Override
-    protected MediaSource buildSource(HostActivity host, String userAgent,
+    protected MediaSource buildSource(
-        TransferListener<? super DataSource> mediaTransferListener) {
+        HostActivity host, String userAgent, TransferListener mediaTransferListener) {
       DataSource.Factory manifestDataSourceFactory = dataSourceFactory != null
           ? dataSourceFactory : new DefaultDataSourceFactory(host, userAgent);
       DataSource.Factory mediaDataSourceFactory = dataSourceFactory != null

testutils/src/main/java/com/google/android/exoplayer2/testutil/ExoHostedTest.java

@@ -41,7 +41,6 @@ import com.google.android.exoplayer2.trackselection.AdaptiveTrackSelection;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.trackselection.MappingTrackSelector;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DefaultBandwidthMeter;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Clock;
@@ -377,8 +376,8 @@ public abstract class ExoHostedTest
   }
 
   @SuppressWarnings("unused")
-  protected abstract MediaSource buildSource(HostActivity host, String userAgent,
+  protected abstract MediaSource buildSource(
-      TransferListener<? super DataSource> mediaTransferListener);
+      HostActivity host, String userAgent, TransferListener mediaTransferListener);
 
   @SuppressWarnings("unused")
   protected void onPlayerErrorInternal(ExoPlaybackException error) {

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java

@@ -25,7 +25,6 @@ import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.chunk.ChunkSampleStream;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.MimeTypes;
 import java.util.ArrayList;
@@ -40,7 +39,7 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
 
   private final Allocator allocator;
   private final FakeChunkSource.Factory chunkSourceFactory;
-  private final @Nullable TransferListener<? super DataSource> transferListener;
+  private final @Nullable TransferListener transferListener;
   private final long durationUs;
 
   private Callback callback;
@@ -53,7 +52,7 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
       Allocator allocator,
       FakeChunkSource.Factory chunkSourceFactory,
       long durationUs,
-      @Nullable TransferListener<? super DataSource> transferListener) {
+      @Nullable TransferListener transferListener) {
     super(trackGroupArray, eventDispatcher);
     this.allocator = allocator;
     this.chunkSourceFactory = chunkSourceFactory;

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaSource.java

@@ -24,7 +24,6 @@ import com.google.android.exoplayer2.source.MediaSourceEventListener;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.TransferListener;
 
 /**
@@ -53,7 +52,7 @@ public class FakeAdaptiveMediaSource extends FakeMediaSource {
       TrackGroupArray trackGroupArray,
       Allocator allocator,
       EventDispatcher eventDispatcher,
-      @Nullable TransferListener<? super DataSource> transferListener) {
+      @Nullable TransferListener transferListener) {
     Period period = timeline.getPeriod(id.periodIndex, new Period());
     return new FakeAdaptiveMediaPeriod(
         trackGroupArray,

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeChunkSource.java

@@ -57,7 +57,7 @@ public final class FakeChunkSource implements ChunkSource {
     public FakeChunkSource createChunkSource(
         TrackSelection trackSelection,
         long durationUs,
-        @Nullable TransferListener<? super DataSource> transferListener) {
+        @Nullable TransferListener transferListener) {
       FakeAdaptiveDataSet dataSet =
           dataSetFactory.createDataSet(trackSelection.getTrackGroup(), durationUs);
       dataSourceFactory.setFakeDataSet(dataSet);

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java

@@ -40,11 +40,11 @@ public class FakeDataSource extends BaseDataSource {
    */
   public static class Factory implements DataSource.Factory {
 
-    protected final TransferListener<? super DataSource> transferListener;
+    protected final TransferListener transferListener;
     protected FakeDataSet fakeDataSet;
     protected boolean isNetwork;
 
-    public Factory(@Nullable TransferListener<? super DataSource> transferListener) {
+    public Factory(@Nullable TransferListener transferListener) {
       this.transferListener = transferListener;
     }
 
@@ -83,9 +83,7 @@ public class FakeDataSource extends BaseDataSource {
   }
 
   public FakeDataSource(
-      FakeDataSet fakeDataSet,
+      FakeDataSet fakeDataSet, @Nullable TransferListener transferListener, boolean isNetwork) {
-      @Nullable TransferListener<? super DataSource> transferListener,
-      boolean isNetwork) {
     super(isNetwork);
     Assertions.checkNotNull(fakeDataSet);
     this.fakeDataSet = fakeDataSet;

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java

@@ -35,7 +35,6 @@ import com.google.android.exoplayer2.source.MediaSourceEventListener.MediaLoadDa
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.upstream.Allocator;
-import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
@@ -61,7 +60,7 @@ public class FakeMediaSource extends BaseMediaSource {
   private boolean preparedSource;
   private boolean releasedSource;
   private Handler sourceInfoRefreshHandler;
-  private @Nullable TransferListener<? super DataSource> transferListener;
+  private @Nullable TransferListener transferListener;
 
   /**
    * Creates a {@link FakeMediaSource}. This media source creates {@link FakeMediaPeriod}s with a
@@ -92,7 +91,7 @@ public class FakeMediaSource extends BaseMediaSource {
   public synchronized void prepareSourceInternal(
       ExoPlayer player,
       boolean isTopLevelSource,
-      @Nullable TransferListener<? super DataSource> mediaTransferListener) {
+      @Nullable TransferListener mediaTransferListener) {
     assertThat(preparedSource).isFalse();
     transferListener = mediaTransferListener;
     preparedSource = true;
@@ -206,7 +205,7 @@ public class FakeMediaSource extends BaseMediaSource {
       TrackGroupArray trackGroupArray,
       Allocator allocator,
       EventDispatcher eventDispatcher,
-      @Nullable TransferListener<? super DataSource> transferListener) {
+      @Nullable TransferListener transferListener) {
     return new FakeMediaPeriod(trackGroupArray, eventDispatcher);
   }