Deprecate flag quic_extract_x509_subject_using_certificate_view,

PiperOrigin-RevId: 353799817
Change-Id: I53a4edb7850e70cf289ea9598026de425e85e79b
diff --git a/quic/core/crypto/quic_crypto_server_config.cc b/quic/core/crypto/quic_crypto_server_config.cc
index 8e9958c..0e9bca8 100644
--- a/quic/core/crypto/quic_crypto_server_config.cc
+++ b/quic/core/crypto/quic_crypto_server_config.cc
@@ -44,7 +44,6 @@
 #include "quic/core/quic_types.h"
 #include "quic/core/quic_utils.h"
 #include "quic/platform/api/quic_bug_tracker.h"
-#include "quic/platform/api/quic_cert_utils.h"
 #include "quic/platform/api/quic_flag_utils.h"
 #include "quic/platform/api/quic_flags.h"
 #include "quic/platform/api/quic_hostname_utils.h"
@@ -1516,27 +1515,15 @@
             context.signed_config()->chain->certs;
         std::string ca_subject;
         if (!certs.empty()) {
-          if (GetQuicReloadableFlag(
-                  quic_extract_x509_subject_using_certificate_view)) {
-            QUIC_RELOADABLE_FLAG_COUNT_N(
-                quic_extract_x509_subject_using_certificate_view, 1, 2);
             std::unique_ptr<CertificateView> view =
                 CertificateView::ParseSingleCertificate(certs[0]);
             if (view != nullptr) {
               absl::optional<std::string> maybe_ca_subject =
                   view->GetHumanReadableSubject();
               if (maybe_ca_subject.has_value()) {
-                QUIC_RELOADABLE_FLAG_COUNT_N(
-                    quic_extract_x509_subject_using_certificate_view, 2, 2);
                 ca_subject = *maybe_ca_subject;
               }
             }
-          } else {
-            absl::string_view ca_subject_view;
-            QuicCertUtils::ExtractSubjectNameFromDERCert(certs[0],
-                                                         &ca_subject_view);
-            ca_subject = std::string(ca_subject_view);
-          }
         }
         QUIC_LOG_EVERY_N_SEC(WARNING, 60)
             << "SCT is expected but it is empty. sni: '"
diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index c6d3d27..8ff6bd6 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -44,7 +44,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_enable_token_based_address_validation, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_encrypted_control_frames, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_encrypted_goaway, true)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_extract_x509_subject_using_certificate_view, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_fix_willing_and_able_to_write2, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_goaway_with_max_stream_id, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_granular_qpack_error_codes, true)
diff --git a/quic/platform/api/quic_cert_utils.h b/quic/platform/api/quic_cert_utils.h
deleted file mode 100644
index cf17615..0000000
--- a/quic/platform/api/quic_cert_utils.h
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2016 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 QUICHE_QUIC_PLATFORM_API_QUIC_CERT_UTILS_H_
-#define QUICHE_QUIC_PLATFORM_API_QUIC_CERT_UTILS_H_
-
-#include "absl/strings/string_view.h"
-#include "quic/platform/api/quic_export.h"
-#include "net/quic/platform/impl/quic_cert_utils_impl.h"
-
-namespace quic {
-
-class QUIC_EXPORT_PRIVATE QuicCertUtils {
- public:
-  static bool ExtractSubjectNameFromDERCert(absl::string_view cert,
-                                            absl::string_view* subject_out) {
-    return QuicCertUtilsImpl::ExtractSubjectNameFromDERCert(cert, subject_out);
-  }
-};
-
-}  // namespace quic
-
-#endif  // QUICHE_QUIC_PLATFORM_API_QUIC_CERT_UTILS_H_