Clean up test runner for ExoPlayer tests.

Currently the ExoPlayerWrapper is used to run tests using an ExoPlayer
implementation. Some properties of the test are set in the constructor, some
are set by overloading the class, others are hard-coded in the
ExoPlayerWrapper class, and a mechanism similar to the existing ActionSchedule
is missing.

This change does the following:
 1. Renames ExoPlayerWrapper to ExoPlayerTestRunner as it better reflects
    its purpose.
 2. Adds an internal Builder to easily set-up the test in a coherent way. This
    allows to only set necessary test components while using defaults for the rest.
 3. Integrate ActionSchedule.
 4. Apply the new structure to the existing tests currently using ExoPlayerWrapper.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=163186578

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

-/*
- * Copyright (C) 2017 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.exoplayer2.testutil;
-
-import android.os.Handler;
-import android.os.HandlerThread;
-import android.util.Pair;
-import com.google.android.exoplayer2.ExoPlaybackException;
-import com.google.android.exoplayer2.ExoPlayer;
-import com.google.android.exoplayer2.ExoPlayerFactory;
-import com.google.android.exoplayer2.PlaybackParameters;
-import com.google.android.exoplayer2.Player;
-import com.google.android.exoplayer2.Renderer;
-import com.google.android.exoplayer2.Timeline;
-import com.google.android.exoplayer2.source.MediaSource;
-import com.google.android.exoplayer2.source.TrackGroupArray;
-import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
-import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
-import java.util.LinkedList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import junit.framework.Assert;
-
-/**
- * Wraps a player with its own handler thread.
- */
-public class ExoPlayerWrapper implements Player.EventListener {
-
-  private final CountDownLatch sourceInfoCountDownLatch;
-  private final CountDownLatch endedCountDownLatch;
-  private final HandlerThread playerThread;
-  private final Handler handler;
-  private final LinkedList<Pair<Timeline, Object>> sourceInfos;
-
-  public ExoPlayer player;
-  public TrackGroupArray trackGroups;
-  public Exception exception;
-
-  // Written only on the main thread.
-  public volatile int positionDiscontinuityCount;
-
-  public ExoPlayerWrapper() {
-    sourceInfoCountDownLatch = new CountDownLatch(1);
-    endedCountDownLatch = new CountDownLatch(1);
-    playerThread = new HandlerThread("ExoPlayerTest thread");
-    playerThread.start();
-    handler = new Handler(playerThread.getLooper());
-    sourceInfos = new LinkedList<>();
-  }
-
-  // Called on the test thread.
-
-  public void blockUntilEnded(long timeoutMs) throws Exception {
-    if (!endedCountDownLatch.await(timeoutMs, TimeUnit.MILLISECONDS)) {
-      exception = new TimeoutException("Test playback timed out waiting for playback to end.");
-    }
-    release();
-    // Throw any pending exception (from playback, timing out or releasing).
-    if (exception != null) {
-      throw exception;
-    }
-  }
-
-  public void blockUntilSourceInfoRefreshed(long timeoutMs) throws Exception {
-    if (!sourceInfoCountDownLatch.await(timeoutMs, TimeUnit.MILLISECONDS)) {
-      throw new TimeoutException("Test playback timed out waiting for source info.");
-    }
-  }
-
-  public void setup(final MediaSource mediaSource, final Renderer... renderers) {
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        try {
-          player = ExoPlayerFactory.newInstance(renderers, new DefaultTrackSelector());
-          player.addListener(ExoPlayerWrapper.this);
-          player.setPlayWhenReady(true);
-          player.prepare(mediaSource);
-        } catch (Exception e) {
-          handleError(e);
-        }
-      }
-    });
-  }
-
-  public void prepare(final MediaSource mediaSource) {
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        try {
-          player.prepare(mediaSource);
-        } catch (Exception e) {
-          handleError(e);
-        }
-      }
-    });
-  }
-
-  public void release() throws InterruptedException {
-    handler.post(new Runnable() {
-      @Override
-      public void run() {
-        try {
-          if (player != null) {
-            player.release();
-          }
-        } catch (Exception e) {
-          handleError(e);
-        } finally {
-          playerThread.quit();
-        }
-      }
-    });
-    playerThread.join();
-  }
-
-  private void handleError(Exception exception) {
-    if (this.exception == null) {
-      this.exception = exception;
-    }
-    endedCountDownLatch.countDown();
-  }
-
-  @SafeVarargs
-  public final void assertSourceInfosEquals(Pair<Timeline, Object>... sourceInfos) {
-    Assert.assertEquals(sourceInfos.length, this.sourceInfos.size());
-    for (Pair<Timeline, Object> sourceInfo : sourceInfos) {
-      Assert.assertEquals(sourceInfo, this.sourceInfos.remove());
-    }
-  }
-
-  // Player.EventListener implementation.
-
-  @Override
-  public void onLoadingChanged(boolean isLoading) {
-    // Do nothing.
-  }
-
-  @Override
-  public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
-    if (playbackState == Player.STATE_ENDED) {
-      endedCountDownLatch.countDown();
-    }
-  }
-
-  @Override
-  public void onRepeatModeChanged(int repeatMode) {
-    // Do nothing.
-  }
-
-  @Override
-  public void onTimelineChanged(Timeline timeline, Object manifest) {
-    sourceInfos.add(Pair.create(timeline, manifest));
-    sourceInfoCountDownLatch.countDown();
-  }
-
-  @Override
-  public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {
-    this.trackGroups = trackGroups;
-  }
-
-  @Override
-  public void onPlayerError(ExoPlaybackException exception) {
-    handleError(exception);
-  }
-
-  @SuppressWarnings("NonAtomicVolatileUpdate")
-  @Override
-  public void onPositionDiscontinuity() {
-    positionDiscontinuityCount++;
-  }
-
-  @Override
-  public void onPlaybackParametersChanged(PlaybackParameters playbackParameters) {
-    // Do nothing.
-  }
-
-}