title: C# implementation of RemoteWebDriver fails to install Chrome extension
body: <p>This ticket is related to ticket <a href="https://github.com/seleniumhq/selenium/issues/1578" rel="nofollow">1578 for Selenium</a> , but my issue is with Chrome and not Firefox as in that ticket.</p>
  
  <p>Installing and configuring an extension works when using a local driver. Doing the same using the C# implementation of RemoteWebDriver does not. Tested this with Chrome.</p>
  
  <p>In my test case, the remote execution was done against SauceLabs. Contacted their support and they verified that installing extensions via RemoteWebDriver works in the JAVA implementation, but fails using the C# implementation.</p>
  
  <p>To quote from their support ticket:</p>
  
  <p>"I tried this myself and I was running into issues on my own end, so this may be a flaw with the C# Selenium bindings with RemoteWebDriver."</p>
  
  <p>My code:</p>
  
  <pre><code>private IWebDriver GetSauceLabsDriver(){
      var outPutDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
      ChromeOptions options = new ChromeOptions();
      options.AddExtensions(outPutDirectory + @"\3.1.3_0.crx");
      //DesiredCapabilities caps = (DesiredCapabilities)options.ToCapabilities();
      var caps = new DesiredCapabilities();
      caps.SetCapability(ChromeOptions.Capability, options.Extensions[0]);
      caps.SetCapability(CapabilityType.BrowserName, "chrome");
      caps.SetCapability(CapabilityType.Version, "53.0");
      caps.SetCapability(CapabilityType.Platform, "Windows 10");
      caps.SetCapability("deviceName", "");
      caps.SetCapability("deviceOrientation", "");
      caps.SetCapability("username", "kin");
      caps.SetCapability("accessKey", "9cd6-438e-a9635b70953d");
      caps.SetCapability("name", TestContext.CurrentContext.Test.Name);
  
      return new RemoteWebDriver(new Uri("http://ondemand.saucelabs.com:80/wd/hub"), caps,
          TimeSpan.FromSeconds(600));
  }
  </code></pre>