code: function Chromedriver(options) {
      if (!options) {
          throw new Error('options is required');
      }
  
      if (!options.port) {
          throw new Error('options.port is required');
      }
  
      this.options = options;
  
      this.child = null;
  }
docs: Chromedriver Constructor
  
  @param {Object} options
  @api public