[Chromoting] Implement HostExperimentSessionPlugin

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_.empty()) {

[Sergey Ulanov, 2017/01/05 20:45:06]

I suggest adding a separate flag to indicate that the configuration has been
received. The value we get in <host-configuration> may be empty

[Hzj_jie, 2017/01/05 23:37:27]

Done.

+    return;
+  }
+
+  const XmlElement* configuration = attachments.FirstNamed(
+      QName(kChromotingXmlNamespace, "host-configuration"));
+  if (!configuration) {
+    return;
+  }
+
+  configuration_ = configuration->BodyText();
+}
+
+const std::string& HostExperimentSessionPlugin::configuration() const {
+  return configuration_;
+}
+
+}  // namespace remoting