Merge "Announce when volume controls appear and disappear." into nyc-dev
am: c14996393a

* commit 'c14996393a976c1ca9ac7cef01a052614a84a7f4':
  Announce when volume controls appear and disappear.

Change-Id: I5299a15e93b2bdf50a55b48b072e3e45dc8a44bf