Enahnced topology and flow stores to extend general store.
diff --git a/core/api/src/main/java/org/onlab/onos/net/topology/TopologyStoreDelegate.java b/core/api/src/main/java/org/onlab/onos/net/topology/TopologyStoreDelegate.java
new file mode 100644
index 0000000..2a19a0c
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/topology/TopologyStoreDelegate.java
@@ -0,0 +1,9 @@
+package org.onlab.onos.net.topology;
+
+import org.onlab.onos.store.StoreDelegate;
+
+/**
+ * Topology store delegate abstraction.
+ */
+public interface TopologyStoreDelegate extends StoreDelegate<TopologyEvent> {
+}