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

net/socket/socket_test_util.h

Index: net/socket/socket_test_util.h
diff --git a/net/socket/socket_test_util.h b/net/socket/socket_test_util.h
index 9446f1cef3b7d48c90e5100b2c3e8ffa08e79e93..950ec486707d1fda3dfbcae55ca3f205abc9ad98 100644
--- a/net/socket/socket_test_util.h
+++ b/net/socket/socket_test_util.h
@@ -46,6 +46,11 @@ class RunLoop;
 
 namespace net {
 
+NET_EXPORT_PRIVATE extern NetworkChangeNotifier::NetworkHandle
+    kDefaultNetworkForTests;
+NET_EXPORT_PRIVATE extern NetworkChangeNotifier::NetworkHandle
+    kNewNetworkForTests;
+
 enum {
   // A private network error code used by the socket test utility classes.
   // If the |result| member of a MockRead is
@@ -764,6 +769,9 @@ class MockUDPClientSocket : public DatagramClientSocket, public AsyncSocket {
   // Address of the "remote" peer we're connected to.
   IPEndPoint peer_addr_;
 
+  // Network that the socket is bound to.
+  NetworkChangeNotifier::NetworkHandle network_;
+
   // While an asynchronous IO is pending, we save our user-buffer state.
   scoped_refptr<IOBuffer> pending_read_buf_;
   int pending_read_buf_len_;