title: How to get instance ID from Firebase?
body: <p>I have successfully got permission grant from the below call. I want to get the instance ID after successful grant.How can I get that Id?</p>
  
  <pre><code>messaging.requestPermission()
    .then(function(result) {
      console.log('Notification permission granted by user.');
    })
    .catch(function(err) {
      console.log('Unable to get permission for notification.', err);
    });
  </code></pre>