[cast_channel] Make CastSocket not inherit from ApiResource

extensions/browser/api/cast_channel/cast_socket_service.h

+// Copyright 2017 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 EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_
+#define EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_
+
+#include <map>
+#include <memory>
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "content/public/browser/browser_thread.h"
+#include "extensions/browser/api/cast_channel/cast_socket.h"
+
+namespace extensions {
+namespace api {
+namespace cast_channel {
+
+// This class adds, removes, and returns cast sockets created by CastChannelAPI
+// to underlying storage.
+// This class is not thread safe. All methods must be called from the IO thread.
+class CastSocketRegistry {
+ public:
+  CastSocketRegistry();
+  ~CastSocketRegistry();
+
+  // Adds |socket| to |sockets_| and returns the new channel_id. Takes ownership
+  // of |socket|.
+  int AddSocket(std::unique_ptr<CastSocket> socket);
+
+  // Removes the CastSocket corresponding to |channel_id| from the
+  // CastSocketRegistry. Returns nullptr if no such CastSocket exists.
+  std::unique_ptr<CastSocket> RemoveSocket(int channel_id);
+
+  // Returns the socket corresponding to |channel_id| if one exists, or nullptr
+  // otherwise.
+  CastSocket* GetSocket(int channel_id) const;
+
+ private:
+  // Used to generate CastSocket id.
+  static int last_channel_id_;
+
+  // The collection of CastSocket keyed by channel_id.
+  std::map<int, std::unique_ptr<CastSocket>> sockets_;
+
+  THREAD_CHECKER(thread_checker_);
+
+  DISALLOW_COPY_AND_ASSIGN(CastSocketRegistry);
+};
+
+// This class associates underlying CastSocketRegistry instance with
+// BrowserContext and makes sure CastSocketRegistry instance is created and
+// destroyed on the IO thread.
+// Instance of this class is created and destroyed on the UI thread.
+class CastSocketService : public KeyedService {
+ public:
+  CastSocketService();
+  ~CastSocketService() override;
+
+  // Creates CastSocketRegistry instance if none exists. Should be called on the
+  // IO thread.
+  CastSocketRegistry* GetOrCreateSocketRegistry();
+
+ private:
+  std::unique_ptr<CastSocketRegistry, content::BrowserThread::DeleteOnIOThread>
+      sockets_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastSocketService);
+};
+
+}  // namespace cast_channel
+}  // namespace api
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_