Switch remoting/protocol to new callbacks

remoting/protocol/session_manager.h

 // Copyright (c) 2011 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.
 
 // The purpose of SessionManager is to facilitate creation of chromotocol
 // sessions. Both host and client use it to establish chromotocol
 // sessions. JingleChromotocolServer implements this inteface using
 // libjingle.
 //
 // OUTGOING SESSIONS
@@ skipping 117 matching lines @@
   // |client_oauth_token| is a short-lived OAuth token identify the client.
   // |config| contains the session configurations that the client supports.
   // |state_change_callback| is called when the connection state changes.
   //
   // Ownership of the |config| is passed to the new session.
   virtual Session* Connect(
       const std::string& host_jid,
       const std::string& host_public_key,
       const std::string& client_token,
       CandidateSessionConfig* config,
-      Session::StateChangeCallback* state_change_callback) = 0;
+      const Session::StateChangeCallback& state_change_callback) = 0;
 
   // Close session manager. Can be called only after all corresponding
   // sessions are destroyed. No callbacks are called after this method
   // returns.
   virtual void Close() = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SessionManager);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_SESSION_MANAGER_H_