title: Can't get WRITE_SETTINGS permission
body: <p>When I have a target API of 23 on Android M Preview 3, I cannot seem to acquire the Manifest.permission.WRITE_SETTTINGS permission.</p>
  <pre><code>requestPermissions(new String[]{Manifest.permission.WRITE_SETTINGS}, 101);
  </code></pre>
  <p>Request permission doesn't bring up the dialog I would expect, but if I make the following call without this permission,</p>
  <pre><code> RingtoneManager.setActualDefaultRingtoneUri(activity, RingtoneManager.TYPE_RINGTONE, ringUri);
  </code></pre>
  <p>The call will except because I don't have the permission.</p>
  <p>I'm not sure where to go from here. Is there a new ringtone API for 23? Or did this permission change just make it impossible for any non-system apps to change the ringtone?</p>