[ew] Add basic classes.

chrome/browser/extensions/api/file_system/entry_watcher_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/extensions/api/file_system/entry_watcher_service_factory.h"
+
+#include "chrome/browser/extensions/api/file_system/entry_watcher_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "content/public/browser/browser_context.h"
+
+namespace extensions {
+
+EntryWatcherServiceFactory* EntryWatcherServiceFactory::GetInstance() {
+  return Singleton<EntryWatcherServiceFactory>::get();
+}
+
+EntryWatcherServiceFactory::EntryWatcherServiceFactory()
+    : BrowserContextKeyedServiceFactory(
+          "EntryWatcherService",
+          BrowserContextDependencyManager::GetInstance()) {
+}
+
+EntryWatcherServiceFactory::~EntryWatcherServiceFactory() {
+}
+
+KeyedService* EntryWatcherServiceFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  return new EntryWatcherService(Profile::FromBrowserContext(context));
+}
+
+bool EntryWatcherServiceFactory::ServiceIsCreatedWithBrowserContext() const {
+  // Required to restore persistent watchers as soon as the profile is loaded.
+  return true;
+}
+
+}  // namespace extensions