role assertion failure is returned to DeviceProvider

Change-Id: Ic5189327c85fa37b3bbfa07d0e285cabae363712
diff --git a/openflow/api/src/main/java/org/onlab/onos/openflow/controller/driver/OpenFlowAgent.java b/openflow/api/src/main/java/org/onlab/onos/openflow/controller/driver/OpenFlowAgent.java
index 1261715..870f10a 100644
--- a/openflow/api/src/main/java/org/onlab/onos/openflow/controller/driver/OpenFlowAgent.java
+++ b/openflow/api/src/main/java/org/onlab/onos/openflow/controller/driver/OpenFlowAgent.java
@@ -2,6 +2,7 @@
 
 import org.onlab.onos.openflow.controller.Dpid;
 import org.onlab.onos.openflow.controller.OpenFlowSwitch;
+import org.onlab.onos.openflow.controller.RoleState;
 import org.projectfloodlight.openflow.protocol.OFMessage;
 
 /**
@@ -74,4 +75,12 @@
      * @param m the message to process
      */
     public void processMessage(Dpid dpid, OFMessage m);
+
+    /**
+     * Notifies the controller that role assertion has failed.
+     *
+     * @param dpid the switch that failed role assertion
+     * @param role the failed role
+     */
+    public void returnRoleAssertFailed(Dpid dpid, RoleState role);
 }