Remove the last of the TLS fallback code.

net/ssl/ssl_config.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 NET_SSL_SSL_CONFIG_H_
 #define NET_SSL_SSL_CONFIG_H_
 
 #include <stdint.h>
 
 #include "base/memory/ref_counted.h"
@@ skipping 23 matching lines @@
   TB_PARAM_RSA2048_PSS = 1,
   TB_PARAM_ECDSAP256 = 2,
 };
 
 // Default minimum protocol version.
 NET_EXPORT extern const uint16_t kDefaultSSLVersionMin;
 
 // Default maximum protocol version.
 NET_EXPORT extern const uint16_t kDefaultSSLVersionMax;
 
-// Default minimum protocol version that it's acceptable to fallback to.
-NET_EXPORT extern const uint16_t kDefaultSSLVersionFallbackMin;
-
 // A collection of SSL-related configuration settings.
 struct NET_EXPORT SSLConfig {
   // Default to revocation checking.
   SSLConfig();
   SSLConfig(const SSLConfig& other);
   ~SSLConfig();
 
   // Returns true if |cert| is one of the certs in |allowed_bad_certs|.
   // The expected cert status is written to |cert_status|. |*cert_status| can
   // be NULL if user doesn't care about the cert status.
@@ skipping 24 matching lines @@
   // local (non-public) trust anchor should be allowed.
   bool sha1_local_anchors_enabled;
 
   // The minimum and maximum protocol versions that are enabled.
   // (Use the SSL_PROTOCOL_VERSION_xxx enumerators defined above.)
   // SSL 2.0 and SSL 3.0 are not supported. If version_max < version_min, it
   // means no protocol versions are enabled.
   uint16_t version_min;
   uint16_t version_max;
 
-  // version_fallback_min contains the minimum version that is acceptable to
-  // fallback to. Versions before this may be tried to see whether they would
-  // have succeeded and thus to give a better message to the user, but the
-  // resulting connection won't be used in these cases.
-  uint16_t version_fallback_min;
-
   // Presorted list of cipher suites which should be explicitly prevented from
   // being used in addition to those disabled by the net built-in policy.
   //
   // Though cipher suites are sent in TLS as "uint8_t CipherSuite[2]", in
   // big-endian form, they should be declared in host byte order, with the
   // first uint8_t occupying the most significant byte.
   // Ex: To disable TLS_RSA_WITH_RC4_128_MD5, specify 0x0004, while to
   // disable TLS_ECDH_ECDSA_WITH_RC4_128_SHA, specify 0xC002.
   std::vector<uint16_t> disabled_cipher_suites;
 
@@ skipping 41 matching lines @@
   // |allowed_bad_certs| that should not trigger an ERR_CERT_* error when
   // calling SSLClientSocket::Connect.  This would normally be done in
   // response to the user explicitly accepting the bad certificate.
   std::vector<CertAndStatus> allowed_bad_certs;
 
   // True if we should send client_cert to the server.
   bool send_client_cert;
 
   bool verify_ev_cert;  // True if we should verify the certificate for EV.
 
-  bool version_fallback;  // True if we are falling back to an older protocol
-                          // version (one still needs to decrement
-                          // version_max).
-
   // If cert_io_enabled is false, then certificate verification will not
   // result in additional HTTP requests. (For example: to fetch missing
   // intermediates or to perform OCSP/CRL fetches.) It also implies that online
   // revocation checking is disabled.
   // NOTE: Only used by NSS.
   bool cert_io_enabled;
 
   // The list of application level protocols supported with ALPN (Application
   // Layer Protocol Negotation), in decreasing order of preference.  Protocols
   // will be advertised in this order during TLS handshake.
   NextProtoVector alpn_protos;
 
   // True if renegotiation should be allowed for the default application-level
   // protocol when the peer negotiates neither ALPN nor NPN.
   bool renego_allowed_default;
 
   // The list of application-level protocols to enable renegotiation for.
   NextProtoVector renego_allowed_for_protos;
 
   scoped_refptr<X509Certificate> client_cert;
   scoped_refptr<SSLPrivateKey> client_private_key;
 };
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_CONFIG_H_