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 5b1ecf40d298e966d2dceea45a9b3f36d30283c7..09b4d7e7a8d25bd7495b2fabb653d2e0399f3e99 100644
--- a/net/http/http_network_session.h
+++ b/net/http/http_network_session.h
@@ -184,7 +184,9 @@ class NET_EXPORT HttpNetworkSession
     bool quic_disable_preconnect_if_0rtt;
     // List of hosts for which QUIC is explicitly whitelisted.
     std::unordered_set<std::string> quic_host_whitelist;
-
+    // If true, active QUIC sessions may be migrated onto new IPs when network
+    // changes.
+    bool quic_migrate_sessions_on_network_change;
     ProxyDelegate* proxy_delegate;
   };