Fix version manager that flip flag in-flight does not make supported versions change.

net/quic/core/quic_protocol.cc

 // Copyright (c) 2012 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.
 
 #include "net/quic/core/quic_protocol.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "net/quic/core/quic_flags.h"
 #include "net/quic/core/quic_utils.h"
@@ skipping 600 matching lines @@
 
 QuicVersionManager::QuicVersionManager(QuicVersionVector supported_versions)
     : enable_version_36_(FLAGS_quic_enable_version_36_v3),
       allowed_supported_versions_(supported_versions),
       filtered_supported_versions_(
           FilterSupportedVersions(supported_versions)) {}
 
 QuicVersionManager::~QuicVersionManager() {}
 
 const QuicVersionVector& QuicVersionManager::GetSupportedVersions() {
-  if (enable_version_36_ != FLAGS_quic_enable_version_36_v3) {
-    enable_version_36_ = FLAGS_quic_enable_version_36_v3;
-    filtered_supported_versions_ =
-        FilterSupportedVersions(allowed_supported_versions_);
-  }
+  MaybeRefilterSupportedVersions();
   return filtered_supported_versions_;
 }
 
+void QuicVersionManager::MaybeRefilterSupportedVersions() {
+  if (enable_version_36_ != FLAGS_quic_enable_version_36_v3) {
+    enable_version_36_ = FLAGS_quic_enable_version_36_v3;
+    RefilterSupportedVersions();
+  }
+}
+
+void QuicVersionManager::RefilterSupportedVersions() {
+  filtered_supported_versions_ =
+      FilterSupportedVersions(allowed_supported_versions_);
+}
+
 AckListenerWrapper::AckListenerWrapper(QuicAckListenerInterface* listener,
                                        QuicPacketLength data_length)
     : ack_listener(listener), length(data_length) {
   DCHECK(listener != nullptr);
 }
 
 AckListenerWrapper::AckListenerWrapper(const AckListenerWrapper& other) =
     default;
 
 AckListenerWrapper::~AckListenerWrapper() {}
@@ skipping 51 matching lines @@
       is_unackable(false),
       has_crypto_handshake(has_crypto_handshake),
       num_padding_bytes(num_padding_bytes),
       retransmission(0) {}
 
 TransmissionInfo::TransmissionInfo(const TransmissionInfo& other) = default;
 
 TransmissionInfo::~TransmissionInfo() {}
 
 }  // namespace net