[Sync] Rework Invalidator-related unit tests

sync/notifier/notifications_disabled_reason.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/notifier/notifications_disabled_reason.h"
 
 #include "base/logging.h"
 
 namespace syncer {
 
@@ skipping 20 matching lines @@
     case notifier::TRANSIENT_NOTIFICATION_ERROR:
       return TRANSIENT_NOTIFICATION_ERROR;
     case notifier::NOTIFICATION_CREDENTIALS_REJECTED:
       return NOTIFICATION_CREDENTIALS_REJECTED;
     default:
       NOTREACHED();
       return TRANSIENT_NOTIFICATION_ERROR;
   }
 }
 
+notifier::NotificationsDisabledReason ToNotifierReasonForTest(
+    NotificationsDisabledReason reason) {
+  switch (reason) {
+    case NO_NOTIFICATION_ERROR:
+      return notifier::NO_NOTIFICATION_ERROR;
+    case TRANSIENT_NOTIFICATION_ERROR:
+      return notifier::TRANSIENT_NOTIFICATION_ERROR;
+    case NOTIFICATION_CREDENTIALS_REJECTED:
+      return notifier::NOTIFICATION_CREDENTIALS_REJECTED;
+    default:
+      NOTREACHED();
+      return notifier::TRANSIENT_NOTIFICATION_ERROR;
+  }
+}
+
 }  // namespace syncer