Implements WebHistoryServiceFactory on iOS

ios/chrome/browser/history/web_history_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_HISTORY_WEB_HISTORY_SERVICE_FACTORY_H_
+#define IOS_CHROME_BROWSER_HISTORY_WEB_HISTORY_SERVICE_FACTORY_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace history {
+class WebHistoryService;
+}
+
+namespace ios {
+
+class ChromeBrowserState;
+
+// Singleton that owns all WebHistoryServices and associates them with
+// ios::ChromeBrowserState.
+class WebHistoryServiceFactory : public BrowserStateKeyedServiceFactory {
+ public:
+  static history::WebHistoryService* GetForBrowserState(
+      ios::ChromeBrowserState* browser_state);
+  static WebHistoryServiceFactory* GetInstance();
+
+ private:
+  friend struct DefaultSingletonTraits<WebHistoryServiceFactory>;
+
+  WebHistoryServiceFactory();
+  ~WebHistoryServiceFactory() override;
+
+  // BrowserStateKeyedServiceFactory implementation.
+  scoped_ptr<KeyedService> BuildServiceInstanceFor(
+      web::BrowserState* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(WebHistoryServiceFactory);
+};
+
+}  // namespace ios
+
+#endif  // IOS_CHROME_BROWSER_HISTORY_WEB_HISTORY_SERVICE_FACTORY_H_