Adding a CDN asset to drupal theme via info file
You can add it in the theme template.php file.

function YOURTHEME_preprocess_html(&amp;$vars) {

      // Load font
      drupal_add_css('//fonts.googleapis.com/css?family=Lato:300,400,700,900', array(
        'type' =&gt; 'external'
      ));

}


Tip: Dont set a protocol to load external resources from Google