title: Repeated call to webkitNotifications.requestPermission() doesn't show permission request in chrome
body: <p>Is it possible to request permission for showing desktop notifications in chrome when user has already denied it ? I don't want to spam user with repeated requests. I have accidentaly clicked the "Deny" button and now every time I try to request permission, nothing shows up. Restart of the browser doesn't help either.</p>
  
  <p>This same thing could happen to user. I've searched but didn't find anything in the Settings or in Developer's tools.</p>