Move RC4 behind a fallback.

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 "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "net/base/net_export.h"
@@ skipping 88 matching lines @@
   // The ciphers listed in |disabled_cipher_suites| will be removed in addition
   // to the above list.
   //
   // Though cipher suites are sent in TLS as "uint8 CipherSuite[2]", in
   // big-endian form, they should be declared in host byte order, with the
   // first uint8 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> disabled_cipher_suites;
 
+  // Enables deprecated cipher suites. Currently, RC4 is deprecated.
+  bool enable_deprecated_cipher_suites;
+
   bool channel_id_enabled;   // True if TLS channel ID extension is enabled.
   bool false_start_enabled;  // True if we'll use TLS False Start.
   // True if the Certificate Transparency signed_certificate_timestamp
   // TLS extension is enabled.
   bool signed_cert_timestamps_enabled;
 
   // require_forward_secrecy, if true, causes only (EC)DHE cipher suites to be
   // enabled. NOTE: this only applies to server sockets currently, although
   // that could be extended if needed.
   bool require_forward_secrecy;
@@ skipping 48 matching lines @@
   // |fastradio_padding_eligible| can be true when |fastradio_padding_enabled|
   // is false: in this case, fastradio padding would not be enabled, but
   // metrics can be collected for experiments.
   bool fastradio_padding_enabled;
   bool fastradio_padding_eligible;
 };
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_CONFIG_H_