[Chromoting] Use HostExperimentSessionPlugin in host

remoting/host/host_experiment_session_plugin.cc

-// 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.
-
-#include "remoting/host/host_experiment_session_plugin.h"
-
-#include "remoting/base/constants.h"
-#include "remoting/host/host_attributes.h"
-
-namespace remoting {
-
-using buzz::QName;
-using buzz::XmlElement;
-
-std::unique_ptr<XmlElement> HostExperimentSessionPlugin::GetNextMessage() {
-  if (attributes_sent_) {
-    return nullptr;
-  }
-  attributes_sent_ = true;
-  std::unique_ptr<XmlElement> attributes(
-      new XmlElement(QName(kChromotingXmlNamespace, "host-attributes")));
-  attributes->SetBodyText(GetHostAttributes());
-  return attributes;
-}
-
-void HostExperimentSessionPlugin::OnIncomingMessage(
-    const XmlElement& attachments) {
-  if (configuration_received_) {
-    return;
-  }
-
-  const XmlElement* configuration = attachments.FirstNamed(
-      QName(kChromotingXmlNamespace, "host-configuration"));
-  if (!configuration) {
-    return;
-  }
-
-  configuration_received_ = true;
-  configuration_ = configuration->BodyText();
-}
-
-bool HostExperimentSessionPlugin::configuration_received() const {
-  return configuration_received_;
-}
-
-const std::string& HostExperimentSessionPlugin::configuration() const {
-  return configuration_;
-}
-
-}  // namespace remoting