Don't use sp<>&

because they may end up pointing to NULL after a NULL check was performed.

Bug: 28166152
Change-Id: Iab2ea30395b620628cc6f3d067dd4f6fcda824fe
diff --git a/include/media/IMediaDeathNotifier.h b/include/media/IMediaDeathNotifier.h
index bb3d0d8..aca6678 100644
--- a/include/media/IMediaDeathNotifier.h
+++ b/include/media/IMediaDeathNotifier.h
@@ -30,7 +30,7 @@
     virtual ~IMediaDeathNotifier() { removeObitRecipient(this); }
 
     virtual void died() = 0;
-    static const sp<IMediaPlayerService>& getMediaPlayerService();
+    static const sp<IMediaPlayerService> getMediaPlayerService();
 
 private:
     IMediaDeathNotifier &operator=(const IMediaDeathNotifier &);