deprecate -FLAGS_quic_reloadable_flag_quic_disable_version_34 and remove support for QUIC v34.

net/quic/core/quic_version_manager.h

 // Copyright (c) 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 NET_QUIC_CORE_QUIC_VERSION_MANAGER_H_
 #define NET_QUIC_CORE_QUIC_VERSION_MANAGER_H_
 
 #include "net/quic/core/quic_versions.h"
 #include "net/quic/platform/api/quic_export.h"
 
@@ skipping 21 matching lines @@
 
  private:
   // FLAGS_quic_enable_version_39
   bool enable_version_39_;
   // FLAGS_quic_reloadable_flag_quic_enable_version_38
   bool enable_version_38_;
   // FLAGS_quic_reloadable_flag_quic_enable_version_37
   bool enable_version_37_;
   // FLAGS_quic_reloadable_flag_quic_enable_version_36_v3
   bool enable_version_36_;
-  // FLAGS_quic_reloadable_flag_quic_disable_version_34
-  bool disable_version_34_;
   // The list of versions that may be supported.
   QuicVersionVector allowed_supported_versions_;
   // This vector contains QUIC versions which are currently supported based on
   // flags.
   QuicVersionVector filtered_supported_versions_;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_QUIC_VERSION_MANAGER_H_