Eldbus: added function for getting bus unique name

Summary:
Hello guys,

We are now working on a accessibility support for elementary (ATSPI2) and we need following function to correctly register application.

Reviewers: cedric, raster, lucasdemarchi

Reviewed By: raster

Differential Revision: https://phab.enlightenment.org/D327

src/lib/eldbus/eldbus_connection.h

@@ -157,6 +157,16 @@ EAPI void                  eldbus_connection_event_callback_del(Eldbus_Connectio
  * ELDBUS_TIMEOUT_INFINITE for no timeout
  */
 EAPI Eldbus_Pending *eldbus_connection_send(Eldbus_Connection *conn, Eldbus_Message *msg, Eldbus_Message_Cb cb, const void *cb_data, double timeout) EINA_ARG_NONNULL(1, 2);
+
+/**
+ * @brief Gets unique name assigned by the message bus.
+ *
+ * @param conn connection object to get unique name from.
+ *
+ * @return pointer to unique name string or NULL or error. Returned value
+ * remains valid until connection is free.
+ */
+EAPI const char *eldbus_connection_unique_name_get(Eldbus_Connection *conn) EINA_ARG_NONNULL(1);
 /**
  * @}
  */

src/lib/eldbus/eldbus_core.c

@@ -1536,3 +1536,10 @@ eldbus_connection_pending_del(Eldbus_Connection *conn, Eldbus_Pending *pending)
    conn->pendings = eina_inlist_remove(conn->pendings,
                                        EINA_INLIST_GET(pending));
 }
+
+const char *
+eldbus_connection_unique_name_get(Eldbus_Connection *conn)
+{
+   ELDBUS_CONNECTION_CHECK_RETVAL(conn, NULL);
+   return dbus_bus_get_unique_name(conn->dbus_conn);
+}