Adding file group for vts_treble_sys_prop_test.

Bug: 147720376
Test: m vts_treble_sys_prop_test
Change-Id: I81a0e21a989dd89f8c37adf5a5c739ca0bdfbac0
diff --git a/Android.bp b/Android.bp
index 4973c13..a2f202f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -375,3 +375,12 @@
     reqd_mask: true,
     soc_specific: true,
 }
+
+// For vts_treble_sys_prop_test
+filegroup {
+    name: "private_property_contexts",
+    srcs: ["private/property_contexts"],
+    visibility: [
+        "//test/vts-testcase/security/system_property",
+    ],
+}