Added support for replicating device offline topology events
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStoreMessageSubjects.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStoreMessageSubjects.java
index 58fed70..4b59e3a 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStoreMessageSubjects.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStoreMessageSubjects.java
@@ -3,13 +3,14 @@
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
 
 /**
- * MessageSubjects used by GossipDeviceStore.
+ * MessageSubjects used by GossipDeviceStore peer-peer communication.
  */
 public final class GossipDeviceStoreMessageSubjects {
 
     private GossipDeviceStoreMessageSubjects() {}
 
     public static final MessageSubject DEVICE_UPDATE = new MessageSubject("peer-device-update");
+    public static final MessageSubject DEVICE_OFFLINE = new MessageSubject("peer-device-offline");
     public static final MessageSubject PORT_UPDATE = new MessageSubject("peer-port-update");
     public static final MessageSubject PORT_STATUS_UPDATE = new MessageSubject("peer-port-status-update");
 }