Add distributed lock primitive

Change-Id: I60f4581d5acb5fc9b9a21d4191874bb56348af58
diff --git a/core/api/src/main/java/org/onosproject/store/primitives/DistributedPrimitiveCreator.java b/core/api/src/main/java/org/onosproject/store/primitives/DistributedPrimitiveCreator.java
index 5fad35a..1e68bdb 100644
--- a/core/api/src/main/java/org/onosproject/store/primitives/DistributedPrimitiveCreator.java
+++ b/core/api/src/main/java/org/onosproject/store/primitives/DistributedPrimitiveCreator.java
@@ -25,6 +25,7 @@
 import org.onosproject.store.service.AsyncConsistentMap;
 import org.onosproject.store.service.AsyncConsistentMultimap;
 import org.onosproject.store.service.AsyncConsistentTreeMap;
+import org.onosproject.store.service.AsyncDistributedLock;
 import org.onosproject.store.service.AsyncDistributedSet;
 import org.onosproject.store.service.AsyncDocumentTree;
 import org.onosproject.store.service.AsyncLeaderElector;
@@ -118,6 +119,14 @@
     <E> AsyncDistributedSet<E> newAsyncDistributedSet(String name, Serializer serializer);
 
     /**
+     * Creates a new {@code AsyncDistributedLock}.
+     *
+     * @param name lock name
+     * @return lock
+     */
+    AsyncDistributedLock newAsyncDistributedLock(String name);
+
+    /**
      * Creates a new {@code AsyncLeaderElector}.
      *
      * @param name leader elector name