[Chromoting] Add SessionPlugin in JingleSession

remoting/protocol/session.h

 // Copyright (c) 2012 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_PROTOCOL_SESSION_H_
 #define REMOTING_PROTOCOL_SESSION_H_
 
+#include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "remoting/protocol/errors.h"
 #include "remoting/protocol/session_config.h"
 #include "remoting/protocol/transport.h"
 
 namespace remoting {
 namespace protocol {
 
+class SessionPlugin;
 class Transport;
 
 // Session is responsible for initializing and authenticating both incoming and
 // outgoing connections. It uses TransportInfoSink interface to pass
 // transport-info messages to the transport.
 class Session {
  public:
   enum State {
     // Created, but not connecting yet.
     INITIALIZING,
@@ skipping 50 matching lines @@
 
   // Sets Transport to be used by the session. Must be called before the
   // session becomes AUTHENTICATED. The transport must outlive the session.
   virtual void SetTransport(Transport* transport) = 0;
 
   // Closes connection. EventHandler is guaranteed not to be called after this
   // method returns. |error| specifies the error code in case when the session
   // is being closed due to an error.
   virtual void Close(ErrorCode error) = 0;
 
+  // Attaches a SessionPlugin to handle attachments. |plugin| should not be an
+  // empty std::unique_ptr.
+  virtual void Attach(std::unique_ptr<SessionPlugin> plugin) = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(Session);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_SESSION_H_