Add some empty classes for the embedded SharedWorker.

content/browser/shared_worker/shared_worker_service_impl.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 "content/browser/shared_worker/shared_worker_service_impl.h"
+
+#include "content/common/worker_messages.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/worker_service_observer.h"
+
+namespace content {
+
+SharedWorkerServiceImpl* SharedWorkerServiceImpl::GetInstance() {
+  // TODO(horo): implement this.
+  NOTIMPLEMENTED();
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  return Singleton<SharedWorkerServiceImpl>::get();
+}
+
+SharedWorkerServiceImpl::SharedWorkerServiceImpl() {
+  // TODO(horo): implement this.
+}
+
+SharedWorkerServiceImpl::~SharedWorkerServiceImpl() {
+  // TODO(horo): implement this.
+}
+
+
+bool SharedWorkerServiceImpl::TerminateWorker(int process_id, int route_id) {
+  // TODO(horo): implement this.
+  return false;
+}
+
+std::vector<WorkerService::WorkerInfo> SharedWorkerServiceImpl::GetWorkers() {
+  // TODO(horo): implement this.
+  std::vector<WorkerService::WorkerInfo> results;
+  return results;
+}
+
+void SharedWorkerServiceImpl::AddObserver(WorkerServiceObserver* observer) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  observers_.AddObserver(observer);
+}
+
+void SharedWorkerServiceImpl::RemoveObserver(WorkerServiceObserver* observer) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  observers_.RemoveObserver(observer);
+}
+
+}  // namespace content