StorageService API for creating AsyncDocumentTree primitive

Change-Id: Ib7c3f19beb7b26a5b69161cf972c3c64d0be94b3
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StorageManager.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StorageManager.java
index 25eb3a5..8e04d5a 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StorageManager.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StorageManager.java
@@ -43,6 +43,7 @@
 import org.onosproject.store.serializers.KryoNamespaces;
 import org.onosproject.store.service.AsyncAtomicValue;
 import org.onosproject.store.service.AsyncConsistentMap;
+import org.onosproject.store.service.AsyncDocumentTree;
 import org.onosproject.store.service.AtomicCounterBuilder;
 import org.onosproject.store.service.AtomicValueBuilder;
 import org.onosproject.store.service.ConsistentMap;
@@ -180,6 +181,12 @@
     }
 
     @Override
+    public <V> AsyncDocumentTree<V> getDocumentTree(String name, Serializer serializer) {
+        checkPermission(STORAGE_WRITE);
+        return federatedPrimitiveCreator.newAsyncDocumentTree(name, serializer);
+    }
+
+    @Override
     public List<MapInfo> getMapInfo() {
         return listMapInfo(federatedPrimitiveCreator);
     }