Fix NuPlayer assertion on failure to create AudioTrack

Under heavy media load or monkey/stress testing, more than
32 AudioTracks may be created or memory resources may be scarce.
Remove the assertion on failure to create AudioTrack
and signal MEDIA_ERROR.

Bug: 17319843
Change-Id: I5d4e200b5f50d800046851a33e035cdc6ff10075
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayer.h b/media/libmediaplayerservice/nuplayer/NuPlayer.h
index 6be38a4..1569816 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayer.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayer.h
@@ -188,7 +188,7 @@
         mFlushComplete[1][1] = false;
     }
 
-    void openAudioSink(const sp<AMessage> &format, bool offloadOnly);
+    void tryOpenAudioSinkForOffload(const sp<AMessage> &format, bool hasVideo);
     void closeAudioSink();
 
     status_t instantiateDecoder(bool audio, sp<DecoderBase> *decoder);