Notification player: do not use stream types

Don't go through stream types for the attributes of the
  notification to play when requesting focus

Test: play notification with usage USAGE_NOTIFICATION_EVENT, verify
  that usage is communicated to MediaFocusControl
Bug 30258418

Change-Id: Ieaab969d84728b04a6f34aa8a02cf18ba22d1aca
1 file changed