Guide V2 + a few related code tweaks

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=133022058

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

@@ -44,8 +44,8 @@ import com.google.android.exoplayer2.video.MediaCodecVideoRenderer;
  * Components common to all ExoPlayer implementations are:
  * <ul>
  *   <li>A <b>{@link MediaSource}</b> that defines the media to be played, loads the media, and from
- *   which the loaded media can be read. A MediaSource is injected via {@link #prepare} to prepare
- *   the player for playback. The library provides default implementations for regular media files
+ *   which the loaded media can be read. A MediaSource is injected via {@link #prepare} at the start
+ *   of playback. The library provides default implementations for regular media files
  *   ({@link ExtractorMediaSource}), DASH ({@link DashMediaSource}), SmoothStreaming
  *   ({@link SsMediaSource}) and HLS ({@link HlsMediaSource}), implementations for merging
  *   ({@link MergingMediaSource}) and concatenating ({@link ConcatenatingMediaSource}) other

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

@@ -39,9 +39,11 @@ public final class ExoPlayerFactory {
    *
    * @param context A {@link Context}.
    * @param trackSelector The {@link TrackSelector} that will be used by the instance.
+   * @param loadControl The {@link LoadControl} that will be used by the instance.
    */
-  public static SimpleExoPlayer newSimpleInstance(Context context, TrackSelector trackSelector) {
-    return newSimpleInstance(context, trackSelector, new DefaultLoadControl(), null);
+  public static SimpleExoPlayer newSimpleInstance(Context context, TrackSelector trackSelector,
+      LoadControl loadControl) {
+    return newSimpleInstance(context, trackSelector, loadControl, null);
   }
 
   /**