Implement TLS_FALLBACK_SCSV for SSLClientSocketOpenSSL.

net/socket/ssl_client_socket_openssl.cc

 // 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.
 
 // OpenSSL binding for SSLClientSocket. The class layout and general principle
 // of operation is derived from SSLClientSocketNSS.
 
 #include "net/socket/ssl_client_socket_openssl.h"
 
 #include <errno.h>
@@ skipping 741 matching lines @@
        command.append(name);
      }
   }
   int rv = SSL_set_cipher_list(ssl_, command.c_str());
   // If this fails (rv = 0) it means there are no ciphers enabled on this SSL.
   // This will almost certainly result in the socket failing to complete the
   // handshake at which point the appropriate error is bubbled up to the client.
   LOG_IF(WARNING, rv != 1) << "SSL_set_cipher_list('" << command << "') "
                               "returned " << rv;
 
+  if (ssl_config_.version_fallback)
+    SSL_enable_fallback_scsv(ssl_);
+
   // TLS channel ids.
   if (IsChannelIDEnabled(ssl_config_, channel_id_service_)) {
     SSL_enable_tls_channel_id(ssl_);
   }
 
   return OK;
 }
 
 void SSLClientSocketOpenSSL::DoReadCallback(int rv) {
   // Since Run may result in Read being called, clear |user_read_callback_|
@@ skipping 733 matching lines @@
   return socket->MaybeReplayTransportError(
       bio, cmd, argp, argi, argl, retvalue);
 }
 
 scoped_refptr<X509Certificate>
 SSLClientSocketOpenSSL::GetUnverifiedServerCertificateChain() const {
   return server_cert_;
 }
 
 }  // namespace net