Move RC4 behind a fallback.

net/socket/ssl_client_socket_openssl.cc

Index: net/socket/ssl_client_socket_openssl.cc
diff --git a/net/socket/ssl_client_socket_openssl.cc b/net/socket/ssl_client_socket_openssl.cc
index 34ddeb8d929b3dfc8788485e5048007caf28752e..c930f991fcd8477a80627f4c78b3a86807fe6697 100644
--- a/net/socket/ssl_client_socket_openssl.cc
+++ b/net/socket/ssl_client_socket_openssl.cc
@@ -800,6 +800,9 @@ int SSLClientSocketOpenSSL::Init() {
      }
   }
 
+  if (!ssl_config_.enable_deprecated_cipher_suites)
+    command.append(":!RC4");
+
   // Disable ECDSA cipher suites on platforms that do not support ECDSA
   // signed certificates, as servers may use the presence of such
   // ciphersuites as a hint to send an ECDSA certificate.
@@ -1945,6 +1948,10 @@ std::string SSLClientSocketOpenSSL::GetSessionCacheKey() const {
       NOTREACHED();
   }
 
+  result.append("/");
+  if (ssl_config_.enable_deprecated_cipher_suites)
+    result.append("deprecated");
+
   return result;
 }