Merge "Null check listener before dereferencing for callback." am: 27b9913521
am: 4747e2b9cc

* commit '4747e2b9cc49d27e7c67fa637b32ba997706d269':
  Null check listener before dereferencing for callback.

Change-Id: I2d353b2f44a4d68eba0a98a4bc38a1106dcb874c