[autofill] Sync server card and address metadata.

components/autofill/core/browser/webdata/autofill_webdata_backend.h

 // Copyright 2013 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.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_
 
 class WebDatabase;
 
 namespace autofill {
@@ skipping 13 matching lines @@
   virtual void AddObserver(
       AutofillWebDataServiceObserverOnDBThread* observer) = 0;
 
   // Remove an observer.
   virtual void RemoveObserver(
       AutofillWebDataServiceObserverOnDBThread* observer) = 0;
 
   // Remove expired elements from the database and commit if needed.
   virtual void RemoveExpiredFormElements() = 0;
 
-  // Notifies listeners on the UI thread that multiple changes have been made to
-  // to Autofill records of the database.
-  // NOTE: This method is intended to be called from the DB thread. It
-  // asynchronously notifies listeners on the UI thread.
+  // Notifies listeners on both DB and UI threads that multiple changes have
+  // been made to to Autofill records of the database.
+  // NOTE: This method is intended to be called from the DB thread. The UI
+  // thread notifications are asynchronous.
   virtual void NotifyOfMultipleAutofillChanges() = 0;
 };
 
 } // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_H_