Group event indicating failover of previously used live port

Change-Id: I32749b38d5e4fab93fa97bbf6587bd0dc91db88c
diff --git a/core/api/src/main/java/org/onosproject/net/group/GroupStore.java b/core/api/src/main/java/org/onosproject/net/group/GroupStore.java
index 3b29d61..d2dd992 100644
--- a/core/api/src/main/java/org/onosproject/net/group/GroupStore.java
+++ b/core/api/src/main/java/org/onosproject/net/group/GroupStore.java
@@ -179,4 +179,9 @@
      * @param groupEntries the group entries as received from southbound
      */
     void pushGroupMetrics(DeviceId deviceId, Collection<Group> groupEntries);
+
+    /**
+     * Indicates failover within a failover group.
+     */
+    void notifyOfFailovers(Collection<Group> failoverGroups);
 }