Enforce the RemoteAccessHostRequireCurtain policy on all platforms.

remoting/host/curtaining_host_observer.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_HOST_CURTAINING_HOST_OBSERVER_H_
 #define REMOTING_HOST_CURTAINING_HOST_OBSERVER_H_
 
+#include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "remoting/host/host_status_observer.h"
 
 namespace remoting {
 
 class CurtainMode;
 class ChromotingHost;
 
 class CurtainingHostObserver : public HostStatusObserver {
  public:
   CurtainingHostObserver(CurtainMode *curtain,
                          scoped_refptr<ChromotingHost> host);
   virtual ~CurtainingHostObserver();
 
-  // From HostStatusObserver.
+  // Enables/disables curtaining when one or more clients are connected.
+  // Takes immediate effect if clients are already connected.
+  void SetEnableCurtaining(bool enable);
+
+  // HostStatusObserver interface.
   virtual void OnClientAuthenticated(const std::string& jid) OVERRIDE;
   virtual void OnClientDisconnected(const std::string& jid) OVERRIDE;
 
  private:
   CurtainMode* curtain_;
   scoped_refptr<ChromotingHost> host_;
+  std::set<std::string> active_clients_;
+  bool enable_curtaining_;
 };
 
 }  // namespace remoting
 #endif