Consistent null-checking in MediaRouter.
Consistent null-checking in MediaRouter.

b/19747094

Change-Id: I5f8d086f717a11a9d03874e633471efed787a6c3

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base