ONOS-4972: Augmented UiModelEvents to hold context and memo about the event subject.

Change-Id: Id0e28d8d5d3eb80fba36e0392cc80167effd39bc
diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/UiWebSocket.java b/web/gui/src/main/java/org/onosproject/ui/impl/UiWebSocket.java
index 328207d..e1d403d 100644
--- a/web/gui/src/main/java/org/onosproject/ui/impl/UiWebSocket.java
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/UiWebSocket.java
@@ -96,6 +96,8 @@
         UiSharedTopologyModel sharedModel = directory.get(UiSharedTopologyModel.class);
         UiTopoLayoutService layoutService = directory.get(UiTopoLayoutService.class);
 
+        sharedModel.injectJsonifier(t2json);
+
         topoSession = new UiTopoSession(this, t2json, sharedModel, layoutService);
 
         // FIXME: this is temporary to prevent unhandled events being set to GUI...