Made AudioRecord a subclasss of RefBase

Made AudioRecord a subclass of RefBase to allow using strong
references and solve concurrency issues.

Issue 6254582.

Change-Id: Ic1f3845958f477e8b2d23d3d25bf0f666addcb3b
diff --git a/include/media/AudioRecord.h b/include/media/AudioRecord.h
index 80d2d72..70f79c6 100644
--- a/include/media/AudioRecord.h
+++ b/include/media/AudioRecord.h
@@ -38,7 +38,7 @@
 
 // ----------------------------------------------------------------------------
 
-class AudioRecord
+class AudioRecord : virtual public RefBase
 {
 public: