Revert of [cast_channel] Move cast_channel related files from //extensions to //components

components/cast_channel/cast_socket_service.h

Index: components/cast_channel/cast_socket_service.h
diff --git a/components/cast_channel/cast_socket_service.h b/components/cast_channel/cast_socket_service.h
deleted file mode 100644
index d7d016ba41806bc6f48babb97d43c1526b83308f..0000000000000000000000000000000000000000
--- a/components/cast_channel/cast_socket_service.h
+++ /dev/null
@@ -1,58 +0,0 @@
-// 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 COMPONENTS_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_
-#define COMPONENTS_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_
-
-#include <map>
-#include <memory>
-
-#include "base/macros.h"
-#include "base/threading/thread_checker.h"
-#include "components/cast_channel/cast_socket.h"
-#include "components/keyed_service/core/refcounted_keyed_service.h"
-#include "content/public/browser/browser_thread.h"
-
-namespace cast_channel {
-
-// This class adds, removes, and returns cast sockets created by CastChannelAPI
-// to underlying storage.
-// Instance of this class is created on the UI thread and destroyed on the IO
-// thread. All public API must be called from the IO thread.
-class CastSocketService : public RefcountedKeyedService {
- public:
-  CastSocketService();
-
-  // 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:
-  ~CastSocketService() override;
-
-  // RefcountedKeyedService implementation.
-  void ShutdownOnUIThread() override;
-
-  // 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(CastSocketService);
-};
-
-}  // namespace cast_channel
-
-#endif  // COMPONENTS_CAST_CHANNEL_CAST_CHANNEL_SERVICE_H_