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

net/http/http_network_session.h

Index: net/http/http_network_session.h
diff --git a/net/http/http_network_session.h b/net/http/http_network_session.h
index 1c3d6a992eee371e1669ae0bffdcd4a986d6209b..eed060b1132f343994925f90bcd297dfbbdd76d6 100644
--- a/net/http/http_network_session.h
+++ b/net/http/http_network_session.h
@@ -181,6 +181,9 @@ class NET_EXPORT HttpNetworkSession
     int quic_idle_connection_timeout_seconds;
     // If true, disable preconnections if QUIC can do 0RTT.
     bool quic_disable_preconnect_if_0rtt;
+    // If true, active QUIC sessions may be migrated onto new IPs when network
+    // changes.
+    bool quic_migrate_sessions_on_network_change;
     ProxyDelegate* proxy_delegate;
   };