deprecate -FLAGS_quic_reloadable_flag_quic_disable_version_34 and remove support for QUIC v34.

net/quic/core/quic_version_manager.cc

Index: net/quic/core/quic_version_manager.cc
diff --git a/net/quic/core/quic_version_manager.cc b/net/quic/core/quic_version_manager.cc
index 7b11073e0839da45dbdd948201b13ca1e232ad75..9f257ab86bbe71e96d0e9eb207383efb32196648 100644
--- a/net/quic/core/quic_version_manager.cc
+++ b/net/quic/core/quic_version_manager.cc
@@ -14,7 +14,6 @@ QuicVersionManager::QuicVersionManager(QuicVersionVector supported_versions)
       enable_version_38_(FLAGS_quic_reloadable_flag_quic_enable_version_38),
       enable_version_37_(FLAGS_quic_reloadable_flag_quic_enable_version_37),
       enable_version_36_(FLAGS_quic_reloadable_flag_quic_enable_version_36_v3),
-      disable_version_34_(FLAGS_quic_reloadable_flag_quic_disable_version_34),
       allowed_supported_versions_(supported_versions),
       filtered_supported_versions_(
           FilterSupportedVersions(supported_versions)) {}
@@ -31,14 +30,11 @@ void QuicVersionManager::MaybeRefilterSupportedVersions() {
       enable_version_38_ != FLAGS_quic_reloadable_flag_quic_enable_version_38 ||
       enable_version_37_ != FLAGS_quic_reloadable_flag_quic_enable_version_37 ||
       enable_version_36_ !=
-          FLAGS_quic_reloadable_flag_quic_enable_version_36_v3 ||
-      disable_version_34_ !=
-          FLAGS_quic_reloadable_flag_quic_disable_version_34) {
+          FLAGS_quic_reloadable_flag_quic_enable_version_36_v3) {
     enable_version_39_ = base::GetFlag(FLAGS_quic_enable_version_39);
     enable_version_38_ = FLAGS_quic_reloadable_flag_quic_enable_version_38;
     enable_version_37_ = FLAGS_quic_reloadable_flag_quic_enable_version_37;
     enable_version_36_ = FLAGS_quic_reloadable_flag_quic_enable_version_36_v3;
-    disable_version_34_ = FLAGS_quic_reloadable_flag_quic_disable_version_34;
     RefilterSupportedVersions();
   }
 }