code: function(opt_config, opt_service, opt_flow) {
    var service = opt_service || getDefaultService();
    var executor = executors.createExecutor(service.start());
  
    var capabilities =
        opt_config instanceof Options ? opt_config.toCapabilities() :
        (opt_config || webdriver.Capabilities.chrome());
  
    var driver = webdriver.WebDriver.createSession(
        executor, capabilities, opt_flow);
  
    webdriver.WebDriver.call(
        this, driver.getSession(), executor, driver.controlFlow());
  }
docs: Creates a new WebDriver client for Chrome.
  
  @param {(webdriver.Capabilities|Options)=} opt_config The configuration
  options.
  @param {remote.DriverService=} opt_service The session to use; will use
  the {@link getDefaultService default service} by default.
  @param {webdriver.promise.ControlFlow=} opt_flow The control flow to use, or
  {@code null} to use the currently active flow.
  @constructor
  @extends {webdriver.WebDriver}