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

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 6eabc9d8c4b5d9da2df269fbc6b448a3c49672e0..13a8be19dbf0262b3c42a1ad63483b3f755a73c1 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -153,7 +153,7 @@ class PingAlarm : public QuicAlarm::Delegate {
   explicit PingAlarm(QuicConnection* connection) : connection_(connection) {}
 
   QuicTime OnAlarm() override {
-    connection_->SendPing();
+    connection_->OnPingTimeout();
     return QuicTime::Zero();
   }
 
@@ -1811,10 +1811,13 @@ PeerAddressChangeType QuicConnection::DeterminePeerAddressChangeType() {
   return UNKNOWN;
 }
 
-void QuicConnection::SendPing() {
-  if (retransmission_alarm_->IsSet()) {
-    return;
+void QuicConnection::OnPingTimeout() {
+  if (!retransmission_alarm_->IsSet()) {
+    SendPing();
   }
+}
+
+void QuicConnection::SendPing() {
   packet_generator_.AddControlFrame(QuicFrame(QuicPingFrame()));
 }