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

net/socket/socket_test_util.cc

Index: net/socket/socket_test_util.cc
diff --git a/net/socket/socket_test_util.cc b/net/socket/socket_test_util.cc
index 5b8c7519af76e08f8c776c5e5e33b5d289274497..6ffbd9bbc530505ad63bef7574293ca17c49b322 100644
--- a/net/socket/socket_test_util.cc
+++ b/net/socket/socket_test_util.cc
@@ -1360,7 +1360,7 @@ int DeterministicMockUDPClientSocket::BindToDefaultNetwork() {
 }
 
 NetworkChangeNotifier::NetworkHandle
-DeterministicMockUDPClientSocket::GetBoundNetwork() {
+DeterministicMockUDPClientSocket::GetBoundNetwork() const {
   return NetworkChangeNotifier::kInvalidNetworkHandle;
 }
 
@@ -1746,7 +1746,8 @@ int MockUDPClientSocket::BindToDefaultNetwork() {
   return ERR_NOT_IMPLEMENTED;
 }
 
-NetworkChangeNotifier::NetworkHandle MockUDPClientSocket::GetBoundNetwork() {
+NetworkChangeNotifier::NetworkHandle MockUDPClientSocket::GetBoundNetwork()
+    const {
   return NetworkChangeNotifier::kInvalidNetworkHandle;
 }