* **Electron Version:**
  * 5.0.x
* **Operating System:**
  * macOS 10.14.5

### Expected Behavior
Electron does not crash at exit.

### Actual Behavior
The notifications are sent well, i use the close() function to avoid persistence in Notification Center. 

By doing this every time I quit the application I have a message that warns me that the application did not stop properly.

### To Reproduce
```javascript
const notif = new Notification({title: title, body: body, silent: true})
notif.on('click', () => appEvent.emit('show-window'))
notif.show()
setTimeout(() => notif.close(), 10000)
```
After sending notification(s), close application (app.quit()) and the error will appear.

To no longer have the error after quitting app, i do not use the function close () but my application generates a lot of notifications and I would have preferred to handle that.

shell/browser/api/atom_api_notification.cc
Close();
  if (presenter_) {
    notification_ = presenter_->CreateNotification(this, base::GenerateGUID());
    if (notification_) {
      electron::NotificationOptions options;
      options.title = title_;
      options.subtitle = subtitle_;
      options.msg = body_;
      options.icon_url = GURL();
      options.icon = icon_.AsBitmap();
      options.silent = silent_;
      options.has_reply = has_reply_;
      options.timeout_type = timeout_type_;
      options.reply_placeholder = reply_placeholder_;
      options.actions = actions_;
      options.sound = sound_;
      options.close_button_text = close_button_text_;
      options.urgency = urgency_;
      notification_->Show(options);
    }
  }
}
bool Notification::IsSupported() {
  return !!static_cast<AtomBrowserClient*>(AtomBrowserClient::Get())
               ->GetNotificationPresenter();
}
void Notification::BuildPrototype(v8::Isolate* isolate,