Move preparation from MediaPeriod constructors to prepare().

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134504088

library/src/main/java/com/google/android/exoplayer2/ExoPlayerImplInternal.java

@@ -952,8 +952,9 @@ import java.io.IOException;
           periodStartPositionUs = defaultPosition.second;
         }
         Object newPeriodUid = timeline.getPeriod(newLoadingPeriodIndex, period, true).uid;
-        MediaPeriod newMediaPeriod = mediaSource.createPeriod(newLoadingPeriodIndex, this,
+        MediaPeriod newMediaPeriod = mediaSource.createPeriod(newLoadingPeriodIndex,
             loadControl.getAllocator(), periodStartPositionUs);
+        newMediaPeriod.prepare(this);
         MediaPeriodHolder<T> newPeriodHolder = new MediaPeriodHolder<>(renderers,
             rendererCapabilities, trackSelector, mediaSource, newMediaPeriod, newPeriodUid,
             periodStartPositionUs);

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

@@ -18,7 +18,6 @@ package com.google.android.exoplayer2.source;
 import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
@@ -79,12 +78,11 @@ public final class ConcatenatingMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     int sourceIndex = timeline.getSourceIndexForPeriod(index);
     int periodIndexInSource = index - timeline.getFirstPeriodIndexInSource(sourceIndex);
-    MediaPeriod mediaPeriod = mediaSources[sourceIndex].createPeriod(periodIndexInSource, callback,
+    MediaPeriod mediaPeriod = mediaSources[sourceIndex].createPeriod(periodIndexInSource, allocator,
-        allocator, positionUs);
+        positionUs);
     sourceIndexByMediaPeriod.put(mediaPeriod, sourceIndex);
     return mediaPeriod;
   }

library/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaPeriod.java

@@ -61,7 +61,6 @@ import java.util.Arrays;
   private final Handler eventHandler;
   private final ExtractorMediaSource.EventListener eventListener;
   private final MediaSource.Listener sourceListener;
-  private final Callback callback;
   private final Allocator allocator;
   private final Loader loader;
   private final ExtractorHolder extractorHolder;
@@ -70,6 +69,7 @@ import java.util.Arrays;
   private final Runnable onContinueLoadingRequestedRunnable;
   private final Handler handler;
 
+  private Callback callback;
   private SeekMap seekMap;
   private boolean tracksBuilt;
   private boolean prepared;
@@ -98,20 +98,18 @@ import java.util.Arrays;
    * @param eventHandler A handler for events. May be null if delivery of events is not required.
    * @param eventListener A listener of events. May be null if delivery of events is not required.
    * @param sourceListener A listener to notify when the timeline has been loaded.
-   * @param callback A callback to receive updates from the period.
    * @param allocator An {@link Allocator} from which to obtain media buffer allocations.
    */
   public ExtractorMediaPeriod(Uri uri, DataSource dataSource, Extractor[] extractors,
       int minLoadableRetryCount, Handler eventHandler,
       ExtractorMediaSource.EventListener eventListener, MediaSource.Listener sourceListener,
-      final Callback callback, Allocator allocator) {
+      Allocator allocator) {
     this.uri = uri;
     this.dataSource = dataSource;
     this.minLoadableRetryCount = minLoadableRetryCount;
     this.eventHandler = eventHandler;
     this.eventListener = eventListener;
     this.sourceListener = sourceListener;
-    this.callback = callback;
     this.allocator = allocator;
     loader = new Loader("Loader:ExtractorMediaPeriod");
     extractorHolder = new ExtractorHolder(extractors, this);
@@ -135,8 +133,6 @@ import java.util.Arrays;
     pendingResetPositionUs = C.TIME_UNSET;
     sampleQueues = new DefaultTrackOutput[0];
     length = C.LENGTH_UNSET;
-    loadCondition.open();
-    startLoading();
   }
 
   public void release() {
@@ -154,6 +150,13 @@ import java.util.Arrays;
     released = true;
   }
 
+  @Override
+  public void prepare(Callback callback) {
+    this.callback = callback;
+    loadCondition.open();
+    startLoading();
+  }
+
   @Override
   public void maybeThrowPrepareError() throws IOException {
     maybeThrowError();

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

@@ -23,7 +23,6 @@ import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.extractor.DefaultExtractorsFactory;
 import com.google.android.exoplayer2.extractor.Extractor;
 import com.google.android.exoplayer2.extractor.ExtractorsFactory;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.util.Assertions;
@@ -148,12 +147,11 @@ public final class ExtractorMediaSource implements MediaSource, MediaSource.List
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     Assertions.checkArgument(index == 0);
     return new ExtractorMediaPeriod(uri, dataSourceFactory.createDataSource(),
         extractorsFactory.createExtractors(), minLoadableRetryCount, eventHandler, eventListener,
-        this, callback, allocator);
+        this, allocator);
   }
 
   @Override

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

@@ -19,7 +19,6 @@ import android.util.Log;
 import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
@@ -76,9 +75,8 @@ public final class LoopingMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
+    return childSource.createPeriod(index % childPeriodCount, allocator, positionUs);
-    return childSource.createPeriod(index % childPeriodCount, callback, allocator, positionUs);
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer2/source/MediaPeriod.java

@@ -42,6 +42,17 @@ public interface MediaPeriod extends SequenceableLoader {
 
   }
 
+  /**
+   * Prepares this media period asynchronously.
+   * <p>
+   * {@code callback.onPrepared} is called when preparation completes. If preparation fails,
+   * {@link #maybeThrowPrepareError()} will throw an {@link IOException}.
+   *
+   * @param callback Callback to receive updates from this period, including being notified when
+   *     preparation completes.
+   */
+  void prepare(Callback callback);
+
   /**
    * Throws an error that's preventing the period from becoming prepared. Does nothing if no such
    * error exists.

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

@@ -16,7 +16,6 @@
 package com.google.android.exoplayer2.source;
 
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import java.io.IOException;
 
@@ -54,18 +53,13 @@ public interface MediaSource {
 
   /**
    * Returns a {@link MediaPeriod} corresponding to the period at the specified index.
-   * <p>
-   * {@link Callback#onPrepared(MediaPeriod)} is called after this method has returned, when the new
-   * period is prepared. If preparation fails, {@link MediaPeriod#maybeThrowPrepareError()} will
-   * throw an {@link IOException} if called on the returned instance.
    *
    * @param index The index of the period.
-   * @param callback A callback to receive updates from the period.
    * @param allocator An {@link Allocator} from which to obtain media buffer allocations.
    * @param positionUs The player's current playback position.
    * @return A new {@link MediaPeriod}.
    */
-  MediaPeriod createPeriod(int index, Callback callback, Allocator allocator, long positionUs);
+  MediaPeriod createPeriod(int index, Allocator allocator, long positionUs);
 
   /**
    * Releases the period.

library/src/main/java/com/google/android/exoplayer2/source/MergingMediaPeriod.java

@@ -28,20 +28,27 @@ import java.util.IdentityHashMap;
 
   public final MediaPeriod[] periods;
 
-  private final Callback callback;
   private final IdentityHashMap<SampleStream, Integer> streamPeriodIndices;
 
+  private Callback callback;
   private int pendingChildPrepareCount;
   private TrackGroupArray trackGroups;
 
   private MediaPeriod[] enabledPeriods;
   private SequenceableLoader sequenceableLoader;
 
-  public MergingMediaPeriod(Callback callback, MediaPeriod... periods) {
+  public MergingMediaPeriod(MediaPeriod... periods) {
     this.periods = periods;
-    this.callback = callback;
     streamPeriodIndices = new IdentityHashMap<>();
+  }
+
+  @Override
+  public void prepare(Callback callback) {
+    this.callback = callback;
     pendingChildPrepareCount = periods.length;
+    for (MediaPeriod period : periods) {
+      period.prepare(this);
+    }
   }
 
   @Override

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

@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.source;
 
 import android.support.annotation.IntDef;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import java.io.IOException;
 import java.lang.annotation.Retention;
@@ -117,15 +116,12 @@ public final class MergingMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     MediaPeriod[] periods = new MediaPeriod[mediaSources.length];
-    // The periods are only referenced after they have all been prepared.
-    MergingMediaPeriod mergingPeriod = new MergingMediaPeriod(callback, periods);
     for (int i = 0; i < periods.length; i++) {
-      periods[i] = mediaSources[i].createPeriod(index, mergingPeriod, allocator, positionUs);
+      periods[i] = mediaSources[i].createPeriod(index, allocator, positionUs);
     }
-    return mergingPeriod;
+    return new MergingMediaPeriod(periods);
   }
 
   @Override

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

@@ -51,7 +51,6 @@ import java.util.Arrays;
   private final int eventSourceId;
   private final TrackGroupArray tracks;
   private final ArrayList<SampleStreamImpl> sampleStreams;
-  private final Handler handler;
   /* package */ final Loader loader;
   /* package */ final Format format;
 
@@ -61,7 +60,7 @@ import java.util.Arrays;
 
   public SingleSampleMediaPeriod(Uri uri, DataSource.Factory dataSourceFactory, Format format,
       int minLoadableRetryCount, Handler eventHandler, EventListener eventListener,
-      int eventSourceId, final Callback callback) {
+      int eventSourceId) {
     this.uri = uri;
     this.dataSourceFactory = dataSourceFactory;
     this.format = format;
@@ -71,20 +70,17 @@ import java.util.Arrays;
     this.eventSourceId = eventSourceId;
     tracks = new TrackGroupArray(new TrackGroup(format));
     sampleStreams = new ArrayList<>();
-    handler = new Handler();
     loader = new Loader("Loader:SingleSampleMediaPeriod");
     sampleData = new byte[INITIAL_SAMPLE_SIZE];
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        callback.onPrepared(SingleSampleMediaPeriod.this);
-      }
-    });
   }
 
   public void release() {
     loader.release();
-    handler.removeCallbacksAndMessages(null);
+  }
+
+  @Override
+  public void prepare(Callback callback) {
+    callback.onPrepared(this);
   }
 
   @Override

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

@@ -19,7 +19,6 @@ import android.net.Uri;
 import android.os.Handler;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.util.Assertions;
@@ -95,11 +94,10 @@ public final class SingleSampleMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     Assertions.checkArgument(index == 0);
     return new SingleSampleMediaPeriod(uri, dataSourceFactory, format, minLoadableRetryCount,
-        eventHandler, eventListener, eventSourceId, callback);
+        eventHandler, eventListener, eventSourceId);
   }
 
   @Override

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

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.source.dash;
 
-import android.os.Handler;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener.EventDispatcher;
@@ -49,11 +48,10 @@ import java.util.List;
   private final EventDispatcher eventDispatcher;
   private final long elapsedRealtimeOffset;
   private final LoaderErrorThrower manifestLoaderErrorThrower;
-  private final Callback callback;
   private final Allocator allocator;
   private final TrackGroupArray trackGroups;
-  private final Handler handler;
 
+  private Callback callback;
   private ChunkSampleStream<DashChunkSource>[] sampleStreams;
   private CompositeSequenceableLoader sequenceableLoader;
   private DashManifest manifest;
@@ -63,7 +61,7 @@ import java.util.List;
   public DashMediaPeriod(int id, DashManifest manifest, int index,
       DashChunkSource.Factory chunkSourceFactory,  int minLoadableRetryCount,
       EventDispatcher eventDispatcher, long elapsedRealtimeOffset,
-      LoaderErrorThrower manifestLoaderErrorThrower, Callback callback, Allocator allocator) {
+      LoaderErrorThrower manifestLoaderErrorThrower, Allocator allocator) {
     this.id = id;
     this.manifest = manifest;
     this.index = index;
@@ -72,19 +70,11 @@ import java.util.List;
     this.eventDispatcher = eventDispatcher;
     this.elapsedRealtimeOffset = elapsedRealtimeOffset;
     this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
-    this.callback = callback;
     this.allocator = allocator;
     sampleStreams = newSampleStreamArray(0);
     sequenceableLoader = new CompositeSequenceableLoader(sampleStreams);
     period = manifest.getPeriod(index);
     trackGroups = buildTrackGroups(period);
-    handler = new Handler();
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        DashMediaPeriod.this.callback.onPrepared(DashMediaPeriod.this);
-      }
-    });
   }
 
   public void updateManifest(DashManifest manifest, int index) {
@@ -103,7 +93,12 @@ import java.util.List;
     for (ChunkSampleStream<DashChunkSource> sampleStream : sampleStreams) {
       sampleStream.release();
     }
-    handler.removeCallbacksAndMessages(null);
+  }
+
+  @Override
+  public void prepare(Callback callback) {
+    this.callback = callback;
+    callback.onPrepared(this);
   }
 
   @Override

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

@@ -26,7 +26,6 @@ import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.MediaPeriod;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifestParser;
@@ -171,11 +170,10 @@ public final class DashMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     DashMediaPeriod mediaPeriod = new DashMediaPeriod(firstPeriodId + index, manifest, index,
         chunkSourceFactory, minLoadableRetryCount, eventDispatcher, elapsedRealtimeOffsetMs, loader,
-        callback, allocator);
+        allocator);
     periodsById.put(mediaPeriod.id, mediaPeriod);
     return mediaPeriod;
   }

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

@@ -50,11 +50,11 @@ import java.util.List;
 /* package */ final class HlsMediaPeriod implements MediaPeriod,
     Loader.Callback<ParsingLoadable<HlsPlaylist>>, HlsSampleStreamWrapper.Callback  {
 
+  private final Uri manifestUri;
   private final DataSource.Factory dataSourceFactory;
   private final int minLoadableRetryCount;
   private final EventDispatcher eventDispatcher;
   private final MediaSource.Listener sourceListener;
-  private final Callback callback;
   private final Allocator allocator;
   private final IdentityHashMap<SampleStream, Integer> streamWrapperIndices;
   private final TimestampAdjusterProvider timestampAdjusterProvider;
@@ -64,6 +64,7 @@ import java.util.List;
   private final long preparePositionUs;
   private final Runnable continueLoadingRunnable;
 
+  private Callback callback;
   private int pendingPrepareCount;
   private HlsPlaylist playlist;
   private boolean seenFirstTrackSelection;
@@ -76,13 +77,13 @@ import java.util.List;
 
   public HlsMediaPeriod(Uri manifestUri, DataSource.Factory dataSourceFactory,
       int minLoadableRetryCount, EventDispatcher eventDispatcher,
-      MediaSource.Listener sourceListener, final Callback callback, Allocator allocator,
+      MediaSource.Listener sourceListener, Allocator allocator,
       long positionUs) {
+    this.manifestUri = manifestUri;
     this.dataSourceFactory = dataSourceFactory;
     this.minLoadableRetryCount = minLoadableRetryCount;
     this.eventDispatcher = eventDispatcher;
     this.sourceListener = sourceListener;
-    this.callback = callback;
     this.allocator = allocator;
     streamWrapperIndices = new IdentityHashMap<>();
     timestampAdjusterProvider = new TimestampAdjusterProvider();
@@ -96,11 +97,6 @@ import java.util.List;
         callback.onContinueLoadingRequested(HlsMediaPeriod.this);
       }
     };
-
-    ParsingLoadable<HlsPlaylist> loadable = new ParsingLoadable<>(
-        dataSourceFactory.createDataSource(), manifestUri, C.DATA_TYPE_MANIFEST, manifestParser);
-    long elapsedRealtimeMs = manifestFetcher.startLoading(loadable, this, minLoadableRetryCount);
-    eventDispatcher.loadStarted(loadable.dataSpec, loadable.type, elapsedRealtimeMs);
   }
 
   public void release() {
@@ -111,6 +107,15 @@ import java.util.List;
     }
   }
 
+  @Override
+  public void prepare(Callback callback) {
+    this.callback = callback;
+    ParsingLoadable<HlsPlaylist> loadable = new ParsingLoadable<>(
+        dataSourceFactory.createDataSource(), manifestUri, C.DATA_TYPE_MANIFEST, manifestParser);
+    long elapsedRealtimeMs = manifestFetcher.startLoading(loadable, this, minLoadableRetryCount);
+    eventDispatcher.loadStarted(loadable.dataSpec, loadable.type, elapsedRealtimeMs);
+  }
+
   @Override
   public void maybeThrowPrepareError() throws IOException {
     if (sampleStreamWrappers == null) {

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

@@ -21,7 +21,6 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.MediaPeriod;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.upstream.Allocator;
@@ -73,11 +72,10 @@ public final class HlsMediaSource implements MediaSource {
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     Assertions.checkArgument(index == 0);
     return new HlsMediaPeriod(manifestUri, dataSourceFactory, minLoadableRetryCount,
-        eventDispatcher, sourceListener, callback, allocator, positionUs);
+        eventDispatcher, sourceListener, allocator, positionUs);
   }
 
   @Override

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

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.source.smoothstreaming;
 
-import android.os.Handler;
 import android.util.Base64;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.extractor.mp4.TrackEncryptionBox;
@@ -47,24 +46,22 @@ import java.util.ArrayList;
   private final LoaderErrorThrower manifestLoaderErrorThrower;
   private final int minLoadableRetryCount;
   private final EventDispatcher eventDispatcher;
-  private final Callback callback;
   private final Allocator allocator;
   private final TrackGroupArray trackGroups;
   private final TrackEncryptionBox[] trackEncryptionBoxes;
-  private final Handler handler;
 
+  private Callback callback;
   private SsManifest manifest;
   private ChunkSampleStream<SsChunkSource>[] sampleStreams;
   private CompositeSequenceableLoader sequenceableLoader;
 
   public SsMediaPeriod(SsManifest manifest, SsChunkSource.Factory chunkSourceFactory,
       int minLoadableRetryCount, EventDispatcher eventDispatcher,
-      LoaderErrorThrower manifestLoaderErrorThrower, Callback callback, Allocator allocator) {
+      LoaderErrorThrower manifestLoaderErrorThrower, Allocator allocator) {
     this.chunkSourceFactory = chunkSourceFactory;
     this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
     this.minLoadableRetryCount = minLoadableRetryCount;
     this.eventDispatcher = eventDispatcher;
-    this.callback = callback;
     this.allocator = allocator;
 
     trackGroups = buildTrackGroups(manifest);
@@ -76,16 +73,9 @@ import java.util.ArrayList;
     } else {
       trackEncryptionBoxes = null;
     }
-    handler = new Handler();
     this.manifest = manifest;
     sampleStreams = newSampleStreamArray(0);
     sequenceableLoader = new CompositeSequenceableLoader(sampleStreams);
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        SsMediaPeriod.this.callback.onPrepared(SsMediaPeriod.this);
-      }
-    });
   }
 
   public void updateManifest(SsManifest manifest) {
@@ -100,7 +90,12 @@ import java.util.ArrayList;
     for (ChunkSampleStream<SsChunkSource> sampleStream : sampleStreams) {
       sampleStream.release();
     }
-    handler.removeCallbacksAndMessages(null);
+  }
+
+  @Override
+  public void prepare(Callback callback) {
+    this.callback = callback;
+    callback.onPrepared(this);
   }
 
   @Override

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

@@ -24,7 +24,6 @@ import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener;
 import com.google.android.exoplayer2.source.AdaptiveMediaSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer2.source.MediaPeriod;
-import com.google.android.exoplayer2.source.MediaPeriod.Callback;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest;
@@ -122,11 +121,10 @@ public final class SsMediaSource implements MediaSource,
   }
 
   @Override
-  public MediaPeriod createPeriod(int index, Callback callback, Allocator allocator,
+  public MediaPeriod createPeriod(int index, Allocator allocator, long positionUs) {
-      long positionUs) {
     Assertions.checkArgument(index == 0);
     SsMediaPeriod period = new SsMediaPeriod(manifest, chunkSourceFactory, minLoadableRetryCount,
-        eventDispatcher, manifestLoader, callback, allocator);
+        eventDispatcher, manifestLoader, allocator);
     mediaPeriods.add(period);
     return period;
   }