Create an AutofillBackend interface

components/autofill/browser/webdata/syncable_service_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_BROWSER_WEBDATA_SYNCABLE_SERVICE_BACKEND_H_
+#define COMPONENTS_AUTOFILL_BROWSER_WEBDATA_SYNCABLE_SERVICE_BACKEND_H_
+
+class WebDatabase;
+
+namespace autofill {
+
+class AutofillWebDataServiceObserverOnDBThread;
+
+// Interface for doing Autofill work directly on the DB thread (used by
+// Sync, mostly), without fully exposing the AutofillWebDataBackend to clients.
+class SyncableServiceBackend {

[Ilya Sherman, 2013/05/08 00:39:06]

I still think that it would be better to name this class
"AutofillWebDataBackend", and rename the existing class to
"AutofillWebDataBackendImpl", as is the common pattern in the //content/ API.

[Cait (Slow), 2013/05/08 19:16:01]

Done.

+ public:
+  virtual ~SyncableServiceBackend() {}
+
+  // Get a raw pointer to the WebDatabase.
+  virtual WebDatabase* GetDatabaseOnDB() = 0;

[Ilya Sherman, 2013/05/08 00:39:06]

nit: The "OnDB" suffix seems redundant, since this entire class is meant to be
used only on the DB thread -- right?

[Cait (Slow), 2013/05/08 19:16:01]

Done.

+
+  // Add an observer to be notified of changes on the DB thread.
+  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 RemoveExpiredFormElementsWrapper() = 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.
+  virtual void NotifyOfMultipleAutofillChanges() = 0;
+};
+
+} // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_BROWSER_WEBDATA_SYNCABLE_SERVICE_BACKEND_H_