code: function createDriver(opt_options, opt_service) {
    var service = opt_service || getDefaultService();
    var executor = executors.createExecutor(service.start());
  
    var options = opt_options || new Options();
    if (opt_options instanceof webdriver.Capabilities) {
      // Extract the Chrome-specific options so we do not send unnecessary
      // data across the wire.
      options = Options.fromCapabilities(options);
    }
  
    return webdriver.WebDriver.createSession(
        executor, options.toCapabilities());
  }
docs: Creates a new ChromeDriver session.
  @param {(webdriver.Capabilities|Options)=} opt_options The session options.
  @param {remote.DriverService=} opt_service The session to use; will use
  the {@link getDefaultService default service} by default.
  @return {!webdriver.WebDriver} A new WebDriver instance.