Implement network default set/clear.

(cherry picked from commit 4cc7df247a7ec67da3b5edfb9356077fbbf0150c)

Change-Id: Ib35d54816884c6a6ba28231c9b1f54e362d1d16a
diff --git a/RouteController.h b/RouteController.h
index 65f8f84..1db1da3 100644
--- a/RouteController.h
+++ b/RouteController.h
@@ -27,6 +27,9 @@
     static bool destroyNetwork(unsigned netId, const char* interface, Permission permission);
     static bool modifyNetworkPermission(unsigned netId, const char* interface,
                                         Permission oldPermission, Permission newPermission);
+
+    static bool addDefaultNetwork(const char* interface, Permission permission);
+    static bool removeDefaultNetwork(const char* interface, Permission permission);
 };
 
 #endif  // SYSTEM_NETD_ROUTE_CONTROLLER_H