Provide iOS implementation of BookmarkServerClusterService factory

ios/chrome/browser/enhanced_bookmarks/bookmark_server_cluster_service_factory.h

+// Copyright 2015 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 IOS_CHROME_BROWSER_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_CLUSTER_SERVICE_FACTORY_H_
+#define IOS_CHROME_BROWSER_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_CLUSTER_SERVICE_FACTORY_H_
+
+#include "base/macros.h"
+#include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace ios {
+class ChromeBrowserState;
+}
+
+namespace enhanced_bookmarks {
+
+class BookmarkServerClusterService;
+
+// A factory to create BookmarkServerClusterService and associate them to
+// ios::ChromeBrowserState.
+class BookmarkServerClusterServiceFactory
+    : public BrowserStateKeyedServiceFactory {
+ public:
+  static BookmarkServerClusterServiceFactory* GetInstance();
+  static BookmarkServerClusterService* GetForBrowserState(
+      ios::ChromeBrowserState* browser_state);
+
+ private:
+  friend struct DefaultSingletonTraits<BookmarkServerClusterServiceFactory>;
+
+  BookmarkServerClusterServiceFactory();
+  ~BookmarkServerClusterServiceFactory() override;
+
+  KeyedService* BuildServiceInstanceFor(
+      web::BrowserState* context) const override;
+  web::BrowserState* GetBrowserStateToUse(
+      web::BrowserState* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(BookmarkServerClusterServiceFactory);
+};
+
+}  // namespace enhanced_bookmarsk
+
+#endif  // IOS_CHROME_BROWSER_ENHANCED_BOOKMARKS_BOOKMARK_SERVER_CLUSTER_SERVICE_FACTORY_H_