Remove interface probing for IPv6 support from HostResolverImpl

net/dns/host_resolver_impl.h

Index: net/dns/host_resolver_impl.h
diff --git a/net/dns/host_resolver_impl.h b/net/dns/host_resolver_impl.h
index 5bce5ed95e74f2bc156c98b54924e381573372ea..f827b3795282aebdaae0cfc157e4b392379ade8c 100644
--- a/net/dns/host_resolver_impl.h
+++ b/net/dns/host_resolver_impl.h
@@ -150,7 +150,6 @@ class NET_EXPORT HostResolverImpl
   friend class HostResolverImplTest;
   class Job;
   class ProcTask;
-  class IPv6ProbeJob;
   class LoopbackProbeJob;
   class DnsTask;
   class Request;
@@ -188,9 +187,6 @@ class NET_EXPORT HostResolverImpl
                       const RequestInfo& info,
                       AddressList* addresses);
 
-  // Callback from IPv6 probe activity.
-  void IPv6ProbeSetDefaultAddressFamily(AddressFamily address_family);
-
   // Callback from HaveOnlyLoopbackAddresses probe.
   void SetHaveOnlyLoopbackAddresses(bool result);