More scaffolding, add class ServiceWorkerProviderHost.

content/browser/service_worker/service_worker_provider_host.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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_
+#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_
+
+#include <map>
+
+namespace content {
+
+// todo: class comment goes here!
+class ServiceWorkerProviderHost {
+ public:
+  ServiceWorkerProviderHost(int provider_id);
+  ~ServiceWorkerProviderHost();
+
+  int provider_id() const { return provider_id_; }
+
+ private:
+  const int provider_id_;
+};
+
+// For mapping from a provider id to an instance.
+typedef std::map<int, ServiceWorkerProviderHost*> ServiceWorkerProviderHostMap;
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROVIDER_HOST_H_