[Chromoting] Use HostExperimentSessionPlugin in host

remoting/host/client_session.h

Index: remoting/host/client_session.h
diff --git a/remoting/host/client_session.h b/remoting/host/client_session.h
index 15ea6df5bab277e36722aad5ba69c2a8aaaa4d3e..55e06d1f7f4afc00de76e1480228f27c89ae15c5 100644
--- a/remoting/host/client_session.h
+++ b/remoting/host/client_session.h
@@ -19,6 +19,7 @@
 #include "remoting/host/client_session_control.h"
 #include "remoting/host/client_session_details.h"
 #include "remoting/host/desktop_environment_options.h"
+#include "remoting/host/host_experiment_session_plugin.h"
 #include "remoting/host/host_extension_session_manager.h"
 #include "remoting/host/remote_input_filter.h"
 #include "remoting/protocol/clipboard_echo_filter.h"
@@ -245,6 +246,8 @@ class ClientSession : public base::NonThreadSafe,
   scoped_refptr<protocol::InputEventTimestampsSource>
       event_timestamp_source_for_tests_;
 
+  HostExperimentSessionPlugin host_experiment_session_plugin_;
+
   // Used to disable callbacks to |this| once DisconnectSession() has been
   // called.
   base::WeakPtrFactory<ClientSessionControl> weak_factory_;