[Sync] Rename csync namespace to syncer

sync/notifier/sync_notifier_observer.h

Index: sync/notifier/sync_notifier_observer.h
diff --git a/sync/notifier/sync_notifier_observer.h b/sync/notifier/sync_notifier_observer.h
index 1c2f1e8af5c1addfe247194b5d82b9d4265cbc98..b09770d4fabd4651c03319ce3c8b19970a3b022d 100644
--- a/sync/notifier/sync_notifier_observer.h
+++ b/sync/notifier/sync_notifier_observer.h
@@ -9,7 +9,7 @@
 #include "sync/internal_api/public/syncable/model_type_payload_map.h"
 #include "sync/notifier/notifications_disabled_reason.h"
 
-namespace csync {
+namespace syncer {
 
 enum IncomingNotificationSource {
   // The server is notifying us that one or more datatypes have stale data.
@@ -38,6 +38,6 @@ class SyncNotifierObserver {
   virtual ~SyncNotifierObserver() {}
 };
 
-}  // namespace csync
+}  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_SYNC_NOTIFIER_OBSERVER_H_