Revert "Playlist API: add Playlist and PlaylistTest"

This reverts commit 5c2806ec.

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

@@ -13,14 +13,16 @@
  * See the License for the specific language governing permissions and
  * See the License for the specific language governing permissions and
  * limitations under the License.
  * limitations under the License.
  */
  */
-package com.google.android.exoplayer2;
+package com.google.android.exoplayer2.source;
 
 
 import android.util.Pair;
 import android.util.Pair;
-import com.google.android.exoplayer2.source.ShuffleOrder;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Assertions;
 
 
 /** Abstract base class for the concatenation of one or more {@link Timeline}s. */
 /** Abstract base class for the concatenation of one or more {@link Timeline}s. */
-public abstract class AbstractConcatenatedTimeline extends Timeline {
+/* package */ abstract class AbstractConcatenatedTimeline extends Timeline {
 
 
   private final int childCount;
   private final int childCount;
   private final ShuffleOrder shuffleOrder;
   private final ShuffleOrder shuffleOrder;

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

@@ -19,7 +19,6 @@ import android.os.Handler;
 import android.os.Message;
 import android.os.Message;
 import androidx.annotation.GuardedBy;
 import androidx.annotation.GuardedBy;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
-import com.google.android.exoplayer2.AbstractConcatenatedTimeline;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource.MediaSourceHolder;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource.MediaSourceHolder;

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

@@ -16,7 +16,6 @@
 package com.google.android.exoplayer2.source;
 package com.google.android.exoplayer2.source;
 
 
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
-import com.google.android.exoplayer2.AbstractConcatenatedTimeline;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Player;