Remove interface probing for IPv6 support from HostResolverImpl

chrome/browser/net/connection_tester.cc

Index: chrome/browser/net/connection_tester.cc
diff --git a/chrome/browser/net/connection_tester.cc b/chrome/browser/net/connection_tester.cc
index 71c5b2d2dc457980a54cb51afecbd3867a0f4306..8314d2fb610148506c992f70ecb822a68d9b703d 100644
--- a/chrome/browser/net/connection_tester.cc
+++ b/chrome/browser/net/connection_tester.cc
@@ -159,12 +159,7 @@ class ExperimentURLRequestContext : public net::URLRequestContext {
         resolver->SetDefaultAddressFamily(net::ADDRESS_FAMILY_IPV4);
         break;
       case ConnectionTester::HOST_RESOLVER_EXPERIMENT_IPV6_PROBE: {
-        // Note that we don't use impl->ProbeIPv6Support() since that finishes
-        // asynchronously and may not take effect in time for the test.
-        // So instead we will probe synchronously (might take 100-200 ms).
-        net::AddressFamily family = net::TestIPv6Support().ipv6_supported ?
-            net::ADDRESS_FAMILY_UNSPECIFIED : net::ADDRESS_FAMILY_IPV4;
-        resolver->SetDefaultAddressFamily(family);
+        // The system HostResolver will probe by default.
         break;
       }
       default: