[Chromoting] Use HostExperimentSessionPlugin in host

remoting/host/host_session_options.h

Index: remoting/host/host_session_options.h
diff --git a/remoting/host/host_session_options.h b/remoting/host/host_session_options.h
index e302b4b4554ee82d09643441541b34989c08c8f5..9834ad07f37cd128d89a753fd67a350955dbbaa4 100644
--- a/remoting/host/host_session_options.h
+++ b/remoting/host/host_session_options.h
@@ -12,7 +12,6 @@
 #include "base/optional.h"
 
 namespace remoting {
-namespace protocol {
 
 // Session based host options sending from client. This class parses and stores
 // session configuration from client side to control the behavior of other host
@@ -22,6 +21,8 @@ class HostSessionOptions final {
   HostSessionOptions();
   ~HostSessionOptions();
 
+  HostSessionOptions(const std::string& parameter);
+
   // Appends one key-value pair into current instance.
   void Append(const std::string& key, const std::string& value);
 
@@ -46,7 +47,6 @@ class HostSessionOptions final {
   DISALLOW_COPY_AND_ASSIGN(HostSessionOptions);
 };
 
-}  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_HOST_SESSION_OPTIONS_H_