Merge "NuPlayer: guard mSource when it\'s accessed on external looper." into nyc-dev
am: 2cfa562

* commit '2cfa562090dfce35e43cb787e5c1692475bb12a1':
  NuPlayer: guard mSource when it's accessed on external looper.

Change-Id: Ieca82514752fae2dcd051b514088b9ef608acb7e