Add unit tests for RetailDemoModeService.

Bug: 30571518
Change-Id: I33b1ae9f22a609088c0ad0cd247fe91ccc23bdaa
diff --git a/services/tests/servicestests/Android.mk b/services/tests/servicestests/Android.mk
index fb8d814..9cfc312 100644
--- a/services/tests/servicestests/Android.mk
+++ b/services/tests/servicestests/Android.mk
@@ -17,6 +17,7 @@
     services.core \
     services.devicepolicy \
     services.net \
+    services.retaildemo \
     services.usage \
     easymocklib \
     guava \