Pref service: add support for tracked prefs.

services/preferences/tracked/tracked_persistent_pref_store_factory.h

+// Copyright 2017 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 SERVICES_PREFERENCES_TRACKED_TRACKED_PERSISTENT_PREF_STORE_FACTORY_H_
+#define SERVICES_PREFERENCES_TRACKED_TRACKED_PERSISTENT_PREF_STORE_FACTORY_H_
+
+#include <utility>
+#include "services/preferences/public/interfaces/preferences_configuration.mojom.h"
+
+namespace base {
+class DictionaryValue;
+class SequencedWorkerPool;
+}
+
+class PersistentPrefStore;
+
+PersistentPrefStore* CreateTrackedPersistentPrefStore(
+    prefs::mojom::TrackedPersistentPrefStoreConfigurationPtr config,
+    base::SequencedWorkerPool* worker_pool);
+
+// TODO(sammc): This should move somewhere more appropriate in the longer term.
+void InitializeMasterPrefsTracking(
+    prefs::mojom::TrackedPersistentPrefStoreConfigurationPtr configuration,
+    base::DictionaryValue* master_prefs);
+
+#endif  // SERVICES_PREFERENCES_TRACKED_TRACKED_PERSISTENT_PREF_STORE_FACTORY_H_