title: How to get the unique user ID in a chrome extension using OAuth?
body: <p>I am using the <code>identity</code> permission in my manifest file and in my JavaScript code I use <code>chrome.identity.getAuthToken({ 'interactive': true }, function( token )</code> to get the use identification token.</p>
  
  <p>How do I get the unique user ID or e-mail address? Preferrably without adding new permissions.</p>