Revert of Renaming Gnubby and RemoteSecurityKey files/classes/members

remoting/host/security_key/security_key_extension.h

-// Copyright 2016 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_SECURITY_KEY_SECURITY_KEY_EXTENSION_H_
-#define REMOTING_HOST_SECURITY_KEY_SECURITY_KEY_EXTENSION_H_
-
-#include <memory>
-#include <string>
-
-#include "base/macros.h"
-#include "remoting/host/host_extension.h"
-
-namespace remoting {
-
-class ClientSessionDetails;
-class HostExtensionSession;
-
-// SecurityKeyExtension extends HostExtension to enable Security Key support.
-class SecurityKeyExtension : public HostExtension {
- public:
-  SecurityKeyExtension();
-  ~SecurityKeyExtension() override;
-
-  // HostExtension interface.
-  std::string capability() const override;
-  std::unique_ptr<HostExtensionSession> CreateExtensionSession(
-      ClientSessionDetails* client_session_details,
-      protocol::ClientStub* client_stub) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(SecurityKeyExtension);
-};
-
-}  // namespace remoting
-
-#endif  // REMOTING_HOST_SECURITY_KEY_SECURITY_KEY_EXTENSION_H_