anchor.diff:  
     // TODO: Implement completion callback. On completion, sounds should
     // also be removed from the list of playing sounds.
  -  SoundCompleteCallback callback;
  +  SoundEffectStreamCallback onSoundComplete;
   
     MediaPlayerProxy _player;
   }
   
  -SoundEffectPlayer _sharedSoundPool;
  +SoundEffectPlayer _sharedSoundEffectPlayer;
   
   class SoundEffectPlayer {
   
     static SoundEffectPlayer sharedInstance() {
  -    if (_sharedSoundPool == null) {
  -      _sharedSoundPool = new SoundEffectPlayer();
  +    if (_sharedSoundEffectPlayer == null) {
  +      _sharedSoundEffectPlayer = new SoundEffectPlayer();
       }
  -    return _sharedSoundPool;
  +    return _sharedSoundEffectPlayer;
     }
   
     SoundEffectPlayer() {
  
positive.code:       double volume = 1.0,
        double pitch = 1.0,
        double pan = 0.0,
        SoundCompleteCallback callback = null]) {
  
      // Create new PlayingSound object
      SoundEffectStream playingSound = new SoundEffectStream(
  
negative.code:     this.volume,
      this.pitch,
      this.pan,
      this.onSoundComplete
    );
  
    // TODO: Make these properties work
  