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

net/udp/datagram_client_socket.h

Index: net/udp/datagram_client_socket.h
diff --git a/net/udp/datagram_client_socket.h b/net/udp/datagram_client_socket.h
index ac4632ed2e33ff27fbf1a2a8fb7f3f365660e2fe..5a967475506f749239fdb8453d142b1f67820e47 100644
--- a/net/udp/datagram_client_socket.h
+++ b/net/udp/datagram_client_socket.h
@@ -25,6 +25,10 @@ class NET_EXPORT_PRIVATE DatagramClientSocket : public DatagramSocket,
   // Returns a net error code.
   virtual int BindToNetwork(NetworkChangeNotifier::NetworkHandle network) = 0;
 
+  // Same as BindToNetwork, except that the current default network is used.
+  // Returns a net error code.
+  virtual int BindToDefaultNetwork() = 0;
+
   // Initialize this socket as a client socket to server at |address|.
   // Returns a network error code.
   virtual int Connect(const IPEndPoint& address) = 0;