Refactor sync notifier out of sync api.

chrome/browser/sync/notifier/sync_notifier_factory.h

+// Copyright (c) 2011 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 CHROME_BROWSER_SYNC_NOTIFIER_SYNC_NOTIFIER_FACTORY_H_
+#define CHROME_BROWSER_SYNC_NOTIFIER_SYNC_NOTIFIER_FACTORY_H_
+
+namespace sync_notifier {
+class SyncNotifier;
+
+// Class to instantiate various implementations of the SyncNotifier interface.
+class SyncNotifierFactory {
+ public:
+  SyncNotifierFactory() {}
+  ~SyncNotifierFactory() {}
+
+  // Creates the appropriate sync notifier.
+  SyncNotifier* CreateSyncNotifier();
+ private:
+};
+}  // namespace sync_notifier
+
+#endif  // CHROME_BROWSER_SYNC_NOTIFIER_SYNC_NOTIFIER_FACTORY_H_