Added ability to force mastership re-balancing between instances from the GUI.

Change-Id: I98e56deb3e2b00df630ed85b596c8e35b3d6efab
diff --git a/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewWebSocket.java b/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewWebSocket.java
index 84e2e02..7477e60 100644
--- a/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewWebSocket.java
+++ b/web/gui/src/main/java/org/onlab/onos/gui/TopologyViewWebSocket.java
@@ -27,6 +27,7 @@
 import org.onlab.onos.event.AbstractEventAccumulator;
 import org.onlab.onos.event.Event;
 import org.onlab.onos.event.EventAccumulator;
+import org.onlab.onos.mastership.MastershipAdminService;
 import org.onlab.onos.mastership.MastershipEvent;
 import org.onlab.onos.mastership.MastershipListener;
 import org.onlab.onos.net.ConnectPoint;
@@ -233,6 +234,9 @@
             requestSummary(event);
         } else if (type.equals("cancelSummary")) {
             cancelSummary(event);
+
+        } else if (type.equals("equalizeMasters")) {
+            equalizeMasters(event);
         }
     }
 
@@ -449,6 +453,12 @@
     }
 
 
+    // Forces mastership role rebalancing.
+    private void equalizeMasters(ObjectNode event) {
+        directory.get(MastershipAdminService.class).balanceRoles();
+    }
+
+
     // Adds all internal listeners.
     private void addListeners() {
         clusterService.addListener(clusterListener);