[fsp] Introduce file_system_provider::Service class for the FileSystemProvider API.

chrome/browser/chromeos/file_system_provider/service_factory.cc

+// Copyright 2014 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.
+
+#include "chrome/browser/chromeos/file_system_provider/service_factory.h"
+
+#include "chrome/browser/chromeos/file_system_provider/service.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+
+namespace chromeos {
+namespace file_system_provider {
+
+// static
+Service* ServiceFactory::Get(content::BrowserContext* context) {
+  return static_cast<Service*>(
+      GetInstance()->GetServiceForBrowserContext(context, true));
+}
+
+ServiceFactory* ServiceFactory::GetInstance() {
+  return Singleton<ServiceFactory>::get();
+}
+
+ServiceFactory::ServiceFactory()
+    : BrowserContextKeyedServiceFactory(
+          "Service",
+          BrowserContextDependencyManager::GetInstance()) {}
+
+ServiceFactory::~ServiceFactory() {}
+
+KeyedService* ServiceFactory::BuildServiceInstanceFor(
+    content::BrowserContext* profile) const {
+  return new Service(static_cast<Profile*>(profile));
+}
+
+bool ServiceFactory::ServiceIsCreatedWithBrowserContext() const { return true; }
+
+}  // namespace file_system_provider
+}  // namespace chromeos