constructor(brand, useUach, fallbackVersion) {
    /** @private @const {string} */
    this.brand_ = brand;

    /** @private @const {!Version} */
    this.version_ = new Version(fallbackVersion);

    /** @private @const {boolean} */
    this.useUach_ = useUach;
  }
@param {string} brand The brand whose version is retrieved in this
    container.
@param {boolean} useUach Whether to attempt to use the User-Agent Client
    Hints (UACH) API surface.
@param {string} fallbackVersion The fallback version derived from the
    userAgent string.