Configure renegotiations on, then disable after the handshake.

net/socket/ssl_client_socket_impl.cc

Index: net/socket/ssl_client_socket_impl.cc
diff --git a/net/socket/ssl_client_socket_impl.cc b/net/socket/ssl_client_socket_impl.cc
index c993fa8fb23da2d1d58c35731b3801a19283ff11..978a3018d73509e8ae1d09bd8a86972baadc5a3e 100644
--- a/net/socket/ssl_client_socket_impl.cc
+++ b/net/socket/ssl_client_socket_impl.cc
@@ -1042,6 +1042,12 @@ int SSLClientSocketImpl::Init() {
   if (cert_verifier_->SupportsOCSPStapling())
     SSL_enable_ocsp_stapling(ssl_.get());
 
+  // Configure BoringSSL to allow renegotiations. Once the initial handshake
+  // completes, if renegotiations are not allowed, the default reject value will
+  // be restored. This is done in this order to permit a BoringSSL
+  // optimization. See https://crbug.com/boringssl/123.
+  SSL_set_renegotiate_mode(ssl_.get(), ssl_renegotiate_freely);
+
   return OK;
 }
 
@@ -1180,8 +1186,8 @@ int SSLClientSocketImpl::DoHandshakeComplete(int result) {
   SSL_get0_signed_cert_timestamp_list(ssl_.get(), &sct_list, &sct_list_len);
   set_signed_cert_timestamps_received(sct_list_len != 0);
 
-  if (IsRenegotiationAllowed())
-    SSL_set_renegotiate_mode(ssl_.get(), ssl_renegotiate_freely);
+  if (!IsRenegotiationAllowed())
+    SSL_set_renegotiate_mode(ssl_.get(), ssl_renegotiate_never);
 
   uint16_t signature_algorithm = SSL_get_peer_signature_algorithm(ssl_.get());
   if (signature_algorithm != 0) {