On client address changes, only migrate QUIC connections when client address changes are considered…

net/quic/quic_protocol.h

Index: net/quic/quic_protocol.h
diff --git a/net/quic/quic_protocol.h b/net/quic/quic_protocol.h
index 0c04ce7968edb9b7af953e74fe584db2a658dd7c..3db1304f8d092794f5d0284d3d5ec1cbf33b4a35 100644
--- a/net/quic/quic_protocol.h
+++ b/net/quic/quic_protocol.h
@@ -986,6 +986,24 @@ enum EncryptionLevel {
   NUM_ENCRYPTION_LEVELS,
 };
 
+
+enum PeerAddressChangeType {
+  NO_CHANGE,
+  // Peer address changes which are considered to be cause by NATs. Currently,
+  // IPv4 address change with /24 does not change is considered to be cause by
+  // NATs.
+  NAT_PORT_REBINDING,
+  IPV4_SUBNET_REBINDING,
+  // IPv6 related address changes.
+  IPV4_TO_IPV6,
+  IPV6_TO_IPV4,
+  IPV6_TO_IPV6,
+  // This type is used when we always allow peer address changes.
+  UNKNOWN,
+  // All other peer address change types.
+  UNSPECIFIED,
+};
+
 struct NET_EXPORT_PRIVATE QuicFrame {
   QuicFrame();
   explicit QuicFrame(QuicPaddingFrame padding_frame);