Revert 224617 "Revert 195406 "[net/dns] Test IPv6 support via UD..."

net/dns/host_resolver_impl.cc

Index: net/dns/host_resolver_impl.cc
===================================================================
--- net/dns/host_resolver_impl.cc	(revision 224662)
+++ net/dns/host_resolver_impl.cc	(working copy)
@@ -2023,32 +2023,35 @@
   AddressFamily effective_address_family = info.address_family();
 
   if (info.address_family() == ADDRESS_FAMILY_UNSPECIFIED) {
-    base::TimeTicks start_time = base::TimeTicks::Now();
-    // Google DNS address.
-    const uint8 kIPv6Address[] =
-        { 0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0x00, 0x00,
-          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x88, 0x88 };
-    bool rv6 = IsGloballyReachable(
-        IPAddressNumber(kIPv6Address, kIPv6Address + arraysize(kIPv6Address)));
+    if (probe_ipv6_support_) {
+      base::TimeTicks start_time = base::TimeTicks::Now();
+      // Google DNS address.
+      const uint8 kIPv6Address[] =
+          { 0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x88, 0x88 };
+      IPAddressNumber address(kIPv6Address,
+                              kIPv6Address + arraysize(kIPv6Address));
+      bool rv6 = IsGloballyReachable(address, net_log);
+      if (rv6)
+        net_log.AddEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_IPV6_SUPPORTED);
 
-    UMA_HISTOGRAM_TIMES("Net.IPv6ConnectDuration",
-                        base::TimeTicks::Now() - start_time);
-    if (rv6) {
-      UMA_HISTOGRAM_BOOLEAN("Net.IPv6ConnectSuccessMatch",
-          default_address_family_ == ADDRESS_FAMILY_UNSPECIFIED);
+      UMA_HISTOGRAM_TIMES("Net.IPv6ConnectDuration",
+                          base::TimeTicks::Now() - start_time);
+      if (rv6) {
+        UMA_HISTOGRAM_BOOLEAN("Net.IPv6ConnectSuccessMatch",
+            default_address_family_ == ADDRESS_FAMILY_UNSPECIFIED);
+      } else {
+        UMA_HISTOGRAM_BOOLEAN("Net.IPv6ConnectFailureMatch",
+            default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED);
+
+        effective_address_family = ADDRESS_FAMILY_IPV4;
+        effective_flags |= HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
+      }
     } else {
-      UMA_HISTOGRAM_BOOLEAN("Net.IPv6ConnectFailureMatch",
-          default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED);
+      effective_address_family = default_address_family_;
     }
   }
 
-  if (effective_address_family == ADDRESS_FAMILY_UNSPECIFIED &&
-      default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED) {
-    effective_address_family = default_address_family_;
-    if (ipv6_probe_monitoring_)
-      effective_flags |= HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  }
-
   return Key(info.hostname(), effective_address_family, effective_flags);
 }