[Chromoting] Use HostExperimentSessionPlugin in host

remoting/host/host_experiment_session_plugin.h

-// Copyright 2016 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 REMOTING_HOST_HOST_EXPERIMENT_SESSION_PLUGIN_H_
-#define REMOTING_HOST_HOST_EXPERIMENT_SESSION_PLUGIN_H_
-
-#include <memory>
-#include <string>
-
-#include "remoting/protocol/session_plugin.h"
-#include "third_party/webrtc/libjingle/xmllite/xmlelement.h"
-
-namespace remoting {
-
-// A SessionPlugin implementation to send host attributes to client, and
-// receives experiment settings.
-class HostExperimentSessionPlugin : public protocol::SessionPlugin {
- public:
-  using SessionPlugin::SessionPlugin;
-
-  // protocol::SessionPlug implementation.
-  std::unique_ptr<buzz::XmlElement> GetNextMessage() override;
-
-  void OnIncomingMessage(const buzz::XmlElement& attachments) override;
-
-  // Whether we have received configuration from client.
-  bool configuration_received() const;
-
-  // The configuration sent from client, may be empty.
-  const std::string& configuration() const;
-
- private:
-  bool attributes_sent_ = false;
-  bool configuration_received_ = false;
-  std::string configuration_;
-};
-
-}  // namespace remoting
-
-#endif  // REMOTING_HOST_HOST_EXPERIMENT_SESSION_PLUGIN_H_