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 96515c33779d6fb692bd249714aea857d6229d00..2ded20f2e36d82ea4fe747bcadeafcaaf2f02cd8 100644
--- a/net/socket/socket_test_util.cc
+++ b/net/socket/socket_test_util.cc
@@ -1243,6 +1243,7 @@ MockUDPClientSocket::MockUDPClientSocket(SocketDataProvider* data,
       read_data_(SYNCHRONOUS, ERR_UNEXPECTED),
       need_read_data_(true),
       source_port_(123),
+      network_(NetworkChangeNotifier::kInvalidNetworkHandle),
       pending_read_buf_(NULL),
       pending_read_buf_len_(0),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_NONE)),
@@ -1341,16 +1342,18 @@ const BoundNetLog& MockUDPClientSocket::NetLog() const {
 
 int MockUDPClientSocket::BindToNetwork(
     NetworkChangeNotifier::NetworkHandle network) {
-  return ERR_NOT_IMPLEMENTED;
+  network_ = network;
+  return OK;
 }
 
 int MockUDPClientSocket::BindToDefaultNetwork() {
-  return ERR_NOT_IMPLEMENTED;
+  network_ = kDefaultNetworkForTests;
+  return OK;
 }
 
 NetworkChangeNotifier::NetworkHandle MockUDPClientSocket::GetBoundNetwork()
     const {
-  return NetworkChangeNotifier::kInvalidNetworkHandle;
+  return network_;
 }
 
 int MockUDPClientSocket::Connect(const IPEndPoint& address) {