Revert 273652 "Host extensions"

trunk/src/remoting/host/host_extension.h

-// Copyright 2014 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_HOST_EXTENSION_H_
-#define REMOTING_HOST_HOST_EXTENSION_H_
-
-#include <string>
-
-#include "base/memory/scoped_ptr.h"
-
-namespace remoting {
-
-class ClientSession;
-class HostExtensionSession;
-
-// Extends |ChromotingHost| with new functionality, and can use extension
-// messages to communicate with the client.
-class HostExtension {
- public:
-  virtual ~HostExtension() {}
-
-  // Returns a space-separated list of capabilities provided by this extension.
-  // Capabilities may be used to inform the client of the availability of an
-  // extension. They are merged into the capabilities the host reports to the
-  // client.
-  virtual std::string GetCapabilities() = 0;
-
-  // Creates an extension session, which can handle extension messages for a
-  // client session.
-  // NULL may be returned if |client_session| cannot support this
-  // extension.
-  // |client_session| must outlive the resulting |HostExtensionSession|.
-  virtual scoped_ptr<HostExtensionSession> CreateExtensionSession(
-      ClientSession* client_session) = 0;
-};
-
-}  // namespace remoting
-
-#endif  // REMOTING_HOST_HOST_EXTENSION_H_