Keep a copy of most recent audio played

Change-Id: I6b2f97881c39998a2fae9ab79d669af6c0a37e94
diff --git a/services/audioflinger/FastMixerState.h b/services/audioflinger/FastMixerState.h
index ce0cdb5..bc69c9c 100644
--- a/services/audioflinger/FastMixerState.h
+++ b/services/audioflinger/FastMixerState.h
@@ -76,6 +76,7 @@
     unsigned    mColdGen;       // increment when COLD_IDLE is requested so it's only performed once
     // This might be a one-time configuration rather than per-state
     FastMixerDumpState* mDumpState; // if non-NULL, then update dump state periodically
+    NBAIO_Sink* mTeeSink;       // if non-NULL, then duplicate write()s to this non-blocking sink
 };  // struct FastMixerState
 
 }   // namespace android