Deprecate gfe2_reloadable_flag_quic_add_ssl_error_stack_to_error_detail.

PiperOrigin-RevId: 690719410
diff --git a/quiche/common/quiche_feature_flags_list.h b/quiche/common/quiche_feature_flags_list.h
index 01097c8..710809f 100755
--- a/quiche/common/quiche_feature_flags_list.h
+++ b/quiche/common/quiche_feature_flags_list.h
@@ -10,7 +10,6 @@
 
 QUICHE_FLAG(bool, quiche_reloadable_flag_enable_h3_origin_frame, false, true, "If true, enables support for parsing HTTP/3 ORIGIN frames.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_act_upon_invalid_header, true, true, "If true, reject or send error response code upon receiving invalid request or response headers.")
-QUICHE_FLAG(bool, quiche_reloadable_flag_quic_add_ssl_error_stack_to_error_detail, true, true, "If true, when TlsHandshaker::AdvanceHandshake closes connection due to BoringSSL error, it will include a formatted BoringSSL error stack in the error details.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_add_stream_info_to_idle_close_detail, false, true, "If true, include stream information in idle timeout connection close detail.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_allow_client_enabled_bbr_v2, true, true, "If true, allow client to enable BBRv2 on server via connection option 'B2ON'.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_allow_host_in_request2, true, true, "If true, requests with a host header will be allowed.")
diff --git a/quiche/quic/core/tls_handshaker.cc b/quiche/quic/core/tls_handshaker.cc
index fcb6cae..4c4fb1f 100644
--- a/quiche/quic/core/tls_handshaker.cc
+++ b/quiche/quic/core/tls_handshaker.cc
@@ -154,13 +154,7 @@
   }
   if (ShouldCloseConnectionOnUnexpectedError(ssl_error) &&
       !is_connection_closed()) {
-    std::string ssl_error_stack;
-    if (GetQuicReloadableFlag(quic_add_ssl_error_stack_to_error_detail)) {
-      QUIC_RELOADABLE_FLAG_COUNT(quic_add_ssl_error_stack_to_error_detail);
-      ssl_error_stack = CryptoUtils::GetSSLErrorStack();
-    } else {
-      ERR_print_errors_fp(stderr);
-    }
+    std::string ssl_error_stack = CryptoUtils::GetSSLErrorStack();
     QUIC_VLOG(1) << "SSL_do_handshake failed; SSL_get_error returns "
                  << ssl_error << ", SSLErrorStack: " << ssl_error_stack;
     if (last_tls_alert_.has_value()) {