Don't probe for IPv6 connectivity when resolving IPv6 literals.

net/dns/host_resolver_impl.cc

Index: net/dns/host_resolver_impl.cc
diff --git a/net/dns/host_resolver_impl.cc b/net/dns/host_resolver_impl.cc
index e84a844a32f7c44a275944ea502a1bdebe4fc505..257715ebc691537caefdcc7cbc8da28aaf580f94 100644
--- a/net/dns/host_resolver_impl.cc
+++ b/net/dns/host_resolver_impl.cc
@@ -2154,13 +2154,17 @@ HostResolverImpl::Key HostResolverImpl::GetEffectiveKeyForRequest(
   AddressFamily effective_address_family = info.address_family();
 
   if (info.address_family() == ADDRESS_FAMILY_UNSPECIFIED) {
-    unsigned char ip_number[4];
-    url::Component host_comp(0, info.hostname().size());
-    int num_components;
+    IPAddressNumber ip_number;
     if (probe_ipv6_support_ && !use_local_ipv6_ &&
-        // Don't bother IPv6 probing when resolving IPv4 literals.
-        url::IPv4AddressToNumber(info.hostname().c_str(), host_comp, ip_number,
-                                 &num_components) != url::CanonHostInfo::IPV4) {
+        // When resolving IPv4 literals, there's no need to probe for IPv6.
+        // When resolving IPv6 literals, there's no benefit to artificially
+        // limiting our resolution based on a probe.  We've already
+        // checked that this query is UNSPECIFIED (see info.address_family()
+        // check above) and that default_address_family_ is UNSPECIFIED
+        // (prove_ipv6_support_ is false if default_address_family_ is
+        // set) so the code requesting the resolution should be amenable to
+        // receiving a IPv6 resolution.
+        !ParseIPLiteralToNumber(info.hostname(), &ip_number)) {

[mmenke, 2015/04/13 16:43:51]

Wonder if it'd be cleaner just to move ParseIPLiteralToNumber out of
ResolverHelper, and have the two resolve functions call it directly, before this
method.

[pauljensen, 2015/04/15 01:29:29]

Done.

       // Google DNS address.
       const uint8 kIPv6Address[] =
           { 0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0x00, 0x00,