addFeature(feature) {
    const Feature = shakaAssets.Feature;
    if (feature == Feature.LIVE) {
      // Unmark this feature as being VOD.
      this.features = this.features.filter((feature) => feature != Feature.VOD);
    }
    this.features.push(feature);
    // Sort the features list, so that features are in a predictable order.
    this.features.sort(ShakaDemoAssetInfo.caseLessAlphaComparator_);
    return this;
  }
@param {shakaAssets.Feature} feature
@return {!ShakaDemoAssetInfo}