title: How to set headers in python selenium chrome webdriver
body: <p>I cant find how to set request headers within selenium chrome webdriver (python). I need to set "host" header. I tryed that:</p>
  
  <pre><code>from selenium import webdriver
  from pyvirtualdisplay import Display
  from selenium.webdriver import DesiredCapabilities
  
  
  url = 'http://localhost:888/test'
  
  display = Display(visible=0, size=(800, 800))
  display.start()
  
  desired_capabilities = DesiredCapabilities.CHROME.copy()
  desired_capabilities['chrome.page.customHeaders.host'] = 'test.local'
  
  driver = webdriver.Chrome('/tmp/chromedriver',
                            desired_capabilities=desired_capabilities)
  
  driver.get(url)
  </code></pre>
  
  <p>And result:</p>
  
  <pre><code>GET /test HTTP/1.1
  Host: localhost:888
  Connection: keep-alive
  Upgrade-Insecure-Requests: 1
  User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/53.0.2785.143 Chrome/53.0.2785.143 Safari/537.36
  Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
  Accept-Encoding: gzip, deflate, sdch
  Accept-Language: en-US,en;q=0.8
  </code></pre>
  
  <p>So, I expected header <code>host:test.local</code> but found that <code>Host: localhost:888</code></p>
  
  <p>What I am doing wrong? I cant find how to set headers with Chrome webdriver :(</p>