Migrates QUIC sessions to a new network when old network is (about to be) disconnected.

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index cc7872f5efc962fa7e2d6533fe823dad312db444..81c5e5794642b16cab0159bd96aa7be80d9827a3 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -1178,7 +1178,8 @@ void IOThread::InitializeNetworkSessionParamsFromGlobals(
       &params->quic_idle_connection_timeout_seconds);
   globals.quic_disable_preconnect_if_0rtt.CopyToIfSet(
       &params->quic_disable_preconnect_if_0rtt);
-
+  globals.quic_migrate_sessions_on_network_change.CopyToIfSet(
+      &params->quic_migrate_sessions_on_network_change);
   globals.origin_to_force_quic_on.CopyToIfSet(
       &params->origin_to_force_quic_on);
   params->enable_user_alternate_protocol_ports =
@@ -1317,6 +1318,8 @@ void IOThread::ConfigureQuicGlobals(
     }
     globals->quic_disable_preconnect_if_0rtt.set(
         ShouldQuicDisablePreConnectIfZeroRtt(quic_trial_params));
+    globals->quic_migrate_sessions_on_network_change.set(
+        ShouldQuicMigrateSessionsOnNetworkChange(quic_trial_params));
   }
 
   size_t max_packet_length = GetQuicMaxPacketLength(command_line,
@@ -1574,6 +1577,14 @@ bool IOThread::ShouldQuicDisablePreConnectIfZeroRtt(
   return base::LowerCaseEqualsASCII(
       GetVariationParam(quic_trial_params, "disable_preconnect_if_0rtt"),
       "true");
+
+bool IOThread::ShouldQuicMigrateSessionsOnNetworkChange(
+    const VariationParameters& quic_trial_params) {
+  return base::LowerCaseEqualsASCII(
+      GetVariationParam(quic_trial_params,
+                        "migrate_sessions_on_network_change"),
+      "true");
+  return false;
 }
 
 size_t IOThread::GetQuicMaxPacketLength(