[Sync] Stop accessing BrowserContextKeyedServiceFactory on non-UI thread.

chrome/browser/extensions/api/storage/settings_sync_util.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_SYNC_UTIL_H_
 #define CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_SYNC_UTIL_H_
 
+#include <string>
+
+#include "components/sync/driver/sync_client.h"
 #include "components/sync/model/sync_change.h"
 #include "components/sync/model/sync_data.h"
 
 namespace base {
 class Value;
 }
 
 namespace content {
 class BrowserContext;
 }
 
-namespace syncer {
-class SyncableService;
-}
-
 namespace extensions {
 
 namespace settings_sync_util {
 
 // Creates a syncer::SyncData object for an extension or app setting.
 syncer::SyncData CreateData(
     const std::string& extension_id,
     const std::string& key,
     const base::Value& value,
     syncer::ModelType type);
@@ skipping 13 matching lines @@
     syncer::ModelType type);
 
 // Creates a "delete" sync change for an extension or app setting.
 syncer::SyncChange CreateDelete(
     const std::string& extension_id,
     const std::string& key,
     syncer::ModelType type);
 
 // Returns the sync service for settings. Must be called on the FILE thread.
 // |type| must be either APP_SETTINGS or EXTENSION_SETTINGS.
-syncer::SyncableService* GetSyncableService(content::BrowserContext* context,
-                                            syncer::ModelType type);
+syncer::SyncClient::ServiceProvider GetSyncableServiceProvider(
+    content::BrowserContext* context,
+    syncer::ModelType type);
 
 }  // namespace settings_sync_util
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_SYNC_UTIL_H_