title: Sound does not work in service worker in Chrome desktop push notification
body: <p>I'm trying to play sound in push notification in Chrome browser when I get notification.
  And I have already set the browser push notification on my site but it does not play sound. I'm already going through the option for sound but get no sound.</p>
  
  <pre class="lang-js prettyprint-override"><code>option = {
       'body' : 'This is tst Description',
       'icon' : 'icon.png',
       'silent' : 'false',
       'sound' : 'bell.mp3'
  }
  </code></pre>
  
  <p>If there is any other way to play the sound in the notification, please let me know.</p>