Send Analytics event from background chrome extension

I'm trying to send an event to Google Analytics from background.js (the background script) of my chrome extension.

I put this code in my background.js file

var _gaq = _gaq || [];
_gaq.push(['_setAccount', _AnalyticsCode]);
_gaq.push(['_trackPageview']);

(function() {
  var ga = document.createElement('script');
  ga.type = 'text/javascript';
  ga.async = true;
  ga.src = 'https://ssl.google-analytics.com/ga.js';
  ga.checkProtocolTask = null;
  var s = document.getElementsByTagName('script')[0];
  s.parentNode.insertBefore(ga, s);
})();

and I try to send this event:

 _gaq.push(['_trackEvent', 'event_send', 'event_label');

but Im not seeing the event on Analytics dashboard. I also added to my manifest.json file this line: "content_security_policy": "script-src 'self' https://ssl.google-analytics.com; object-src 'self'", What do I need to do to make it work from the background?