I am new to protractor and I want to be able to run my chrome browser painted or headless. 

So I set up something like this

```
 let chrome = {
     browserName: 'chrome',
     platform: 'MAC',
     'max-duration': '1800',

 };

let chromeHeadless = {
     browserName: 'chrome',     
    chromeOptions: {
      args: [ "--headless", "--disable-gpu", "--window-size=800,600" ]
    }
};

browserDefault = browser.params.browserToUse

exports.config = {
   params: {

    'browserToUse': "get from user'

   },
   capabilities: browserDefault,
 }

```

and i ran this code as 

```
 protractor config.js --params.browserToUse='chromeHeadless' 

```

But this does not work. Protractor fails saying it does not understand "browser.params.browserInput". Whats the right way to make protractor dynamically choose chrome or chromeheadless based on the input