[ew] Add basic classes.

chrome/browser/file_system/entry_watcher_service_factory.h

+// 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.
+
+#ifndef CHROME_BROWSER_FILE_SYSTEM_ENTRY_WATCHER_SERVICE_FACTORY_H_
+#define CHROME_BROWSER_FILE_SYSTEM_ENTRY_WATCHER_SERVICE_FACTORY_H_
+
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+namespace content {
+class BrowserContext;
+}  // namespace content
+
+class EntryWatcherService;
+
+// Creates instances of the EntryWatcherService class.
+class EntryWatcherServiceFactory : public BrowserContextKeyedServiceFactory {
+ public:
+  // Returns a service instance singleton per |context|, after creating it
+  // (if necessary).
+  static EntryWatcherService* Get(content::BrowserContext* context);
+
+  // Returns a service instance for the context if exists. Otherwise, returns
+  // NULL.
+  static EntryWatcherService* FindExisting(content::BrowserContext* context);
+
+  // Gets a singleton instance of the factory.
+  static EntryWatcherServiceFactory* GetInstance();
+
+ private:
+  friend struct DefaultSingletonTraits<EntryWatcherServiceFactory>;
+
+  EntryWatcherServiceFactory();
+  virtual ~EntryWatcherServiceFactory();
+
+  // BrowserContextKeyedServiceFactory overrides:
+  virtual KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* profile) const OVERRIDE;
+  virtual bool ServiceIsCreatedWithBrowserContext() const OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(EntryWatcherServiceFactory);
+};
+
+#endif  // CHROME_BROWSER_FILE_SYSTEM_ENTRY_WATCHER_SERVICE_FACTORY_H_