This:

```js
    if (!MozActivity) {
      console.log('MozActivity unavailable');
      return;
    }

    var activity = new MozActivity({
      name: 'pick',
      data: {
        type: 'webcontacts/contact'
      }
    });

    activity.onsuccess = (function() {
      var details = Utils.getContactDetails(activity.result);
      this.recipients.push({
        name: details.title || details.number,
        phoneNumber: details.number,
        source: 'contacts'
      });
    }).bind(this);

    activity.onerror = (function(e) {
      console.log('WebActivities unavailable? : ' + e);
    }).bind(this);
```

Fixed in new commit