ExoPlayer V2 Refactor - Misc

Delete SingleSampleChunkSource. I don't think it's really
useful for anything, now we have SingleSampleSource.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=113259289

library/src/main/java/com/google/android/exoplayer/chunk/SingleSampleChunkSource.java

-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.android.exoplayer.chunk;
-
-import com.google.android.exoplayer.C;
-import com.google.android.exoplayer.MediaFormat;
-import com.google.android.exoplayer.TrackGroup;
-import com.google.android.exoplayer.upstream.DataSource;
-import com.google.android.exoplayer.upstream.DataSpec;
-
-import java.util.List;
-
-/**
- * A chunk source that provides a single chunk containing a single sample.
- * <p>
- * An example use case for this implementation is to act as the source for loading out-of-band
- * subtitles, where subtitles for the entire video are delivered as a single file.
- */
-public final class SingleSampleChunkSource implements ChunkSource {
-
-  private final DataSource dataSource;
-  private final DataSpec dataSpec;
-  private final Format format;
-  private final long durationUs;
-  private final TrackGroup tracks;
-
-  /**
-   * @param dataSource A {@link DataSource} suitable for loading the sample data.
-   * @param dataSpec Defines the location of the sample.
-   * @param format The format of the sample.
-   * @param durationUs The duration of the sample in microseconds, or {@link C#UNKNOWN_TIME_US} if
-   *     the duration is unknown.
-   * @param mediaFormat The sample media format. May be null.
-   */
-  public SingleSampleChunkSource(DataSource dataSource, DataSpec dataSpec, Format format,
-      long durationUs, MediaFormat mediaFormat) {
-    this.dataSource = dataSource;
-    this.dataSpec = dataSpec;
-    this.format = format;
-    this.durationUs = durationUs;
-    tracks = new TrackGroup(mediaFormat);
-  }
-
-  @Override
-  public boolean prepare() {
-    return true;
-  }
-
-  @Override
-  public TrackGroup getTracks() {
-    return tracks;
-  }
-
-  @Override
-  public void enable(int[] tracks) {
-    // Do nothing.
-  }
-
-  @Override
-  public void continueBuffering(long playbackPositionUs) {
-    // Do nothing.
-  }
-
-  @Override
-  public void getChunkOperation(List<? extends MediaChunk> queue, long playbackPositionUs,
-      ChunkOperationHolder out) {
-    if (!queue.isEmpty()) {
-      // We've already provided the single sample.
-      out.endOfStream = true;
-      return;
-    }
-    out.chunk = initChunk();
-  }
-
-  @Override
-  public void disable(List<? extends MediaChunk> queue) {
-    // Do nothing.
-  }
-
-  @Override
-  public void maybeThrowError() {
-    // Do nothing.
-  }
-
-  @Override
-  public void onChunkLoadCompleted(Chunk chunk) {
-    // Do nothing.
-  }
-
-  @Override
-  public void onChunkLoadError(Chunk chunk, Exception e) {
-    // Do nothing.
-  }
-
-  private SingleSampleMediaChunk initChunk() {
-    return new SingleSampleMediaChunk(dataSource, dataSpec, Chunk.TRIGGER_UNSPECIFIED, format, 0,
-        durationUs, 0, tracks.getFormat(0), null, Chunk.NO_PARENT_ID);
-  }
-
-}