Merge "Adds a null check in NuPlayer::closeAudioSink."

media/libmediaplayerservice/nuplayer/NuPlayer.cpp

@@ -1798,8 +1798,10 @@ void NuPlayer::tryOpenAudioSinkForOffload(
 }
 
 void NuPlayer::closeAudioSink() {
+    if (mRenderer != NULL) {
         mRenderer->closeAudioSink();
     }
+}
 
 void NuPlayer::restartAudio(
         int64_t currentPositionUs, bool forceNonOffload, bool needsToCreateAudioDecoder) {