Add version field to syncer::Invalidation.

sync/notifier/p2p_invalidator.cc

Index: sync/notifier/p2p_invalidator.cc
diff --git a/sync/notifier/p2p_invalidator.cc b/sync/notifier/p2p_invalidator.cc
index 8b54c0417ee8f5f466f309d412d918c11b6e917f..05ec1835379faf101018be0c578c9165ce1062f4 100644
--- a/sync/notifier/p2p_invalidator.cc
+++ b/sync/notifier/p2p_invalidator.cc
@@ -173,7 +173,9 @@ void P2PInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
   const P2PNotificationData notification_data(
       invalidator_client_id_,
       NOTIFY_SELF,
-      ObjectIdSetToInvalidationMap(new_ids, std::string()));
+      ObjectIdSetToInvalidationMap(new_ids,
+                                   Invalidation::kUnknownVersion,
+                                   std::string()));
   SendNotificationData(notification_data);
 }
 
@@ -228,6 +230,7 @@ void P2PInvalidator::OnNotificationsEnabled() {
         invalidator_client_id_,
         NOTIFY_SELF,
         ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(),
+                                     Invalidation::kUnknownVersion,
                                      std::string()));
     SendNotificationData(notification_data);
   }
@@ -263,6 +266,7 @@ void P2PInvalidator::OnIncomingNotification(
         invalidator_client_id_,
         NOTIFY_ALL,
         ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(),
+                                     Invalidation::kUnknownVersion,
                                      std::string()));
   }
   if (!notification_data.IsTargeted(invalidator_client_id_)) {