Add some empty classes for the embedded SharedWorker.

content/browser/worker_host/shared_worker_service_impl.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 CONTENT_BROWSER_WORKER_HOST_SHARED_WORKER_SERVICE_IMPL_H_
+#define CONTENT_BROWSER_WORKER_HOST_SHARED_WORKER_SERVICE_IMPL_H_
+
+#include "base/compiler_specific.h"
+#include "base/memory/singleton.h"
+#include "base/observer_list.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/worker_service.h"
+
+namespace content {
+class WorkerServiceObserver;
+
+// If "enable-embedded-shared-worker" is set this class will be used in stead of
+// WorkerServiceImpl.
+// TODO(horo): implement this class.
+class CONTENT_EXPORT SharedWorkerServiceImpl
+    : public NON_EXPORTED_BASE(WorkerService) {
+ public:
+  // Returns the SharedWorkerServiceImpl singleton.
+  static SharedWorkerServiceImpl* GetInstance();
+
+  // WorkerService implementation:
+  virtual bool TerminateWorker(int process_id, int route_id) OVERRIDE;
+  virtual std::vector<WorkerInfo> GetWorkers() OVERRIDE;
+  virtual void AddObserver(WorkerServiceObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(WorkerServiceObserver* observer) OVERRIDE;
+
+ private:
+  friend struct DefaultSingletonTraits<SharedWorkerServiceImpl>;
+
+  SharedWorkerServiceImpl();
+  virtual ~SharedWorkerServiceImpl();
+
+  ObserverList<WorkerServiceObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(SharedWorkerServiceImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_WORKER_HOST_SHARED_WORKER_SERVICE_IMPL_H_