createEmptyVariant_(id) {
    return {
      id: id,
      language: '',
      disabledUntilTime: 0,
      primary: false,
      audio: null,
      video: null,
      bandwidth: 0,
      allowedByApplication: true,
      allowedByKeySystem: true,
      decodingInfos: [],
    };
  }
Creates an empty Variant.

@param {number} id
@return {!shaka.extern.Variant}
@private