Enable sync for the settings from the Extension Settings API.

chrome/browser/extensions/extension_settings_sync_util.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_EXTENSIONS_EXTENSION_SETTINGS_SYNC_UTIL_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_SYNC_UTIL_H_
+#pragma once
+
+#include "base/values.h"
+#include "chrome/browser/sync/api/sync_data.h"
+#include "chrome/browser/sync/api/sync_change.h"
+
+namespace extension_settings_sync_util {
+
+// Creates a SyncData object for an extension setting.
+SyncData CreateData(
+    const std::string& extension_id,
+    const std::string& key,
+    const Value& value);
+
+// Creates an "add" sync change for an extension setting.
+SyncChange CreateAdd(
+    const std::string& extension_id,
+    const std::string& key,
+    const Value& value);
+
+// Creates an "update" sync change for an extension setting.
+SyncChange CreateUpdate(
+  const std::string& extension_id,
+  const std::string& key,
+  const Value& value);
+
+// Creates a "delete" sync change for an extension setting.
+SyncChange CreateDelete(
+    const std::string& extension_id, const std::string& key);
+
+}  // namespace extension_settings_sync_util
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_SYNC_UTIL_H_