Unhide android.media.AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE

Unhide android.media.AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE
Update android.media.AudioManager.requestAudioFocus() javadoc for the
  new focus type.

Bug 8251963

Change-Id: I7cd69faaf5f0169ee462b91d0aaa75dc6b092107
2 files changed