Treat IPv4-mapped IPv6 addresses as IPv4 addresses.

net/quic/quic_address_mismatch.cc

Index: net/quic/quic_address_mismatch.cc
===================================================================
--- net/quic/quic_address_mismatch.cc	(revision 271511)
+++ net/quic/quic_address_mismatch.cc	(working copy)
@@ -14,9 +14,17 @@
   if (first_address.address().empty() || second_address.address().empty()) {
     return -1;
   }
+  IPAddressNumber first_ip_address = first_address.address();
+  if (IsIPv4Mapped(first_ip_address)) {
+    first_ip_address = ConvertIPv4MappedToIPv4(first_ip_address);
+  }
+  IPAddressNumber second_ip_address = second_address.address();
+  if (IsIPv4Mapped(second_ip_address)) {
+    second_ip_address = ConvertIPv4MappedToIPv4(second_ip_address);
+  }
 
   int sample;
-  if (first_address.address() != second_address.address()) {
+  if (first_ip_address != second_ip_address) {
     sample = QUIC_ADDRESS_MISMATCH_BASE;
   } else if (first_address.port() != second_address.port()) {
     sample = QUIC_PORT_MISMATCH_BASE;
@@ -29,8 +37,8 @@
   //   V6_V6: add 1
   //   V4_V6: add 2
   //   V6_V4: add 3
-  bool first_ipv4 = (first_address.address().size() == kIPv4AddressSize);
-  bool second_ipv4 = (second_address.address().size() == kIPv4AddressSize);
+  bool first_ipv4 = (first_ip_address.size() == kIPv4AddressSize);
+  bool second_ipv4 = (second_ip_address.size() == kIPv4AddressSize);
   if (first_ipv4 != second_ipv4) {
     CHECK_EQ(sample, QUIC_ADDRESS_MISMATCH_BASE);
     sample += 2;