title: Chromedriver --screenshot not working in headless mode?
body: <p>I'm using new chrome driver headless mode (Chrome v59, mac os) with webdriver. but unfortunately, screenshot option given in headless mode is not working for me. following code shows the chrome options configured.</p>
  
  <pre><code>chromeOptions.addArguments("headless");
  chromeOptions.addArguments("disable-gpu");
  chromeOptions.addArguments("window-size=1980x960");
  chromeOptions.addArguments("screenshot");
  </code></pre>
  
  <p>I'm getting unknown chrome error:</p>
  
  <pre><code>unknown error: Chrome failed to start: exited abnormally
    (Driver info: chromedriver=2.30.477690 (c53f4ad87510ee97b5c3425a14c0e79780cdf262),platform=Mac OS X 10.11.6 x86_64) (WARNING: The server did not provide any stacktrace information)
  Command duration or timeout: 60.05 seconds
  Build info: version: '3.4.0', revision: 'unknown', time: 'unknown'
  System info: host: 'ip-192-168-13-242.ec2.internal', ip: '192.168.13.242', os.name: 'Mac OS X', os.arch: 'x86_64', os.version: '10.11.6', java.version: '1.8.0_51'
  Driver info: driver.version: ChromeDriver
          at com.axonix.utilities.SeleniumDriverWrapper.setupNewDriverInstance(SeleniumDriverWrapper.java:78)
          at com.axonix.utilities.SeleniumDriverWrapper.&lt;init&gt;(SeleniumDriverWrapper.java:55)
          at com.axonix.utilities.SeleniumInterface.&lt;init&gt;(SeleniumInterface.java:30)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
          at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
          at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
          at org.picocontainer.injectors.AbstractInjector.newInstance(AbstractInjector.java:145)
          at org.picocontainer.injectors.ConstructorInjector$1.run(ConstructorInjector.java:342)
          at org.picocontainer.injectors.AbstractInjector$ThreadLocalCyclicDependencyGuard.observe(AbstractInjector.java:270)
          at org.picocontainer.injectors.ConstructorInjector.getComponentInstance(ConstructorInjector.java:364)
          at org.picocontainer.injectors.AbstractInjectionFactory$LifecycleAdapter.getComponentInstance(AbstractInjectionFactory.java:56)
          at org.picocontainer.behaviors.AbstractBehavior.getComponentInstance(AbstractBehavior.java:64)
          at org.picocontainer.behaviors.Stored.getComponentInstance(Stored.java:91)
          at org.picocontainer.DefaultPicoContainer.getInstance(DefaultPicoContainer.java:699)
          at org.picocontainer.DefaultPainer.getComponent(DefaultPicoContainer.java:647)
          at org.picocontainer.DefaultPicoContainer.getComponent(DefaultPicoContainer.java:632)
          at org.picocontainer.parameters.BasicComponentParameter$1.resolveInstance(BasicComponentParameter.java:118)
          at org.picocontainer.parameters.ComponentParameter$1.resolveInstance(ComponentParameter.java:136)
          at org.picocontainer.injectors.SingleMemberInjector.getParameter(SingleMemberInjector.java:78)
          at org.picocontainer.injectors.ConstructorInjector$CtorAndAdapters.getParameterArguments(ConstructorInjector.java:309)
          at org.picocontainer.injectors.ConstructorInjector$1.run(ConstructorInjector.java:335)
          at org.picocontainer.injectors.AbstractInjector$ThreadLocalCyclicDependencyGuard.observe(AbstractInjector.java:270)
          at org.picocontainer.injectors.ConstructorInjector.getComponentInstance(ConstructorInjector.java:364)
          at org.picocontainer.injectors.AbstractInjectionFactory$LifecycleAdapter.getComponentInstance(AbstractInjectionFactory.java:56)
          at org.picocontainer.behaviors.AbstractBehavior.getComponentInstance(AbstractBehavior.java:64)
          at org.picocontainer.behaviors.Stored.getComponentInstance(Stored.java:91)
          at org.picocontainer.DefaultPicoContainer.getInstance(DefaultPicoContainer.java:699)
          at org.picocontainer.DefaultPicoContainer.getComponent(DefaultPicoContainer.java:647)
          at org.picocontainer.DefaultPicoContainer.getComponent(DefaultPicoContainer.java:678)
          at cucumber.runtime.java.picocontainer.PicoFactory.getInstance(PicoFactory.java:40)
          at cucumber.runtime.java.JavaStepDefinition.execute(JavaStepDefinition.java:38)
          at cucumber.runtime.StepDefinitionMatch.runStep(StepDefinitionMatch.java:37)
          at cucumber.runtime.Runtime.runStep(Runtime.java:300)
          at cucumber.runtime.model.StepContainer.runStep(StepContainer.java:44)
          at cucumber.runtime.model.StepContainer.runSteps(StepContainer.java:39)
          at cucumber.runtime.model.CucumberScenario.run(CucumberScenario.java:44)
          at cucumber.runtime.model.CucumberFeature.run(CucumberFeature.java:165)
          at cucumber.runtimee.run(Runtime.java:122)
          at cucumber.api.cli.Main.run(Main.java:36)
          at cucumber.api.cli.Main.main(Main.java:18)
  </code></pre>