ONOS-4971: Synthetic Link Data -- WIP

- Enhancing UiRegion to capture the hierarchical (parent/child) relationships captured in the UiTopoLayouts.

Change-Id: I152e0d52d4580b14b679f3387402077f16f61e6a
diff --git a/core/api/src/main/java/org/onosproject/ui/UiTopoLayoutService.java b/core/api/src/main/java/org/onosproject/ui/UiTopoLayoutService.java
index 0036521..c6ae247 100644
--- a/core/api/src/main/java/org/onosproject/ui/UiTopoLayoutService.java
+++ b/core/api/src/main/java/org/onosproject/ui/UiTopoLayoutService.java
@@ -15,6 +15,7 @@
  */
 package org.onosproject.ui;
 
+import org.onosproject.net.region.RegionId;
 import org.onosproject.ui.model.topo.UiTopoLayout;
 import org.onosproject.ui.model.topo.UiTopoLayoutId;
 
@@ -57,6 +58,15 @@
     UiTopoLayout getLayout(UiTopoLayoutId layoutId);
 
     /**
+     * Returns the layout which has the backing region identified by
+     * the given region identifier.
+     *
+     * @param regionId region identifier
+     * @return corresponding layout
+     */
+    UiTopoLayout getLayout(RegionId regionId);
+
+    /**
      * Returns the set of peer layouts of the specified layout. That is,
      * those layouts that share the same parent.
      *