[Chromoting] Implement HostExperimentSessionPlugin

remoting/host/host_experiment_session_plugin.h

Index: remoting/host/host_experiment_session_plugin.h
diff --git a/remoting/host/host_experiment_session_plugin.h b/remoting/host/host_experiment_session_plugin.h
new file mode 100644
index 0000000000000000000000000000000000000000..20627420f40812bbc1747bee3946103744c7db46
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+++ b/remoting/host/host_experiment_session_plugin.h
@@ -0,0 +1,41 @@
+// 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_