Remove unused AppKeepAliveService

apps/app_keep_alive_service.h

-// Copyright 2013 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 APPS_APP_KEEP_ALIVE_SERVICE_H_
-#define APPS_APP_KEEP_ALIVE_SERVICE_H_
-
-#include "apps/app_lifetime_monitor.h"
-#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
-
-namespace apps {
-
-class AppKeepAliveService : public BrowserContextKeyedService,
-                            public AppLifetimeMonitor::Observer {
- public:
-  AppKeepAliveService(content::BrowserContext* context);
-  virtual ~AppKeepAliveService();
-  virtual void Shutdown() OVERRIDE;
-
-  // AppLifetimeMonitor::Observer:
-  virtual void OnAppStart(Profile* profile, const std::string& app_id) OVERRIDE;
-  virtual void OnAppStop(Profile* profile, const std::string& app_id) OVERRIDE;
-  virtual void OnAppActivated(Profile* profile,
-                              const std::string& app_id) OVERRIDE;
-  virtual void OnAppDeactivated(Profile* profile,
-                                const std::string& app_id) OVERRIDE;
-  virtual void OnChromeTerminating() OVERRIDE;
-
- private:
-  content::BrowserContext* context_;
-  std::set<std::string> running_apps_;
-  bool shut_down_;
-
-  DISALLOW_COPY_AND_ASSIGN(AppKeepAliveService);
-};
-
-}  // namespace apps
-
-#endif  // APPS_APP_KEEP_ALIVE_SERVICE_H_