Remove interface probing for IPv6 support from HostResolverImpl

net/dns/host_resolver.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_DNS_HOST_RESOLVER_H_
 #define NET_DNS_HOST_RESOLVER_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 152 matching lines @@
   // has already run or the request was canceled.
   virtual void CancelRequest(RequestHandle req) = 0;
 
   // Sets the default AddressFamily to use when requests have left it
   // unspecified. For example, this could be used to restrict resolution
   // results to AF_INET by passing in ADDRESS_FAMILY_IPV4, or to
   // AF_INET6 by passing in ADDRESS_FAMILY_IPV6.
   virtual void SetDefaultAddressFamily(AddressFamily address_family) {}
   virtual AddressFamily GetDefaultAddressFamily() const;
 
-  // Continuously observe whether IPv6 is supported, and set the allowable
-  // address family to IPv4 iff IPv6 is not supported.
-  virtual void ProbeIPv6Support();
-
   // Enable or disable the built-in asynchronous DnsClient.
   virtual void SetDnsClientEnabled(bool enabled);
 
   // Returns the HostResolverCache |this| uses, or NULL if there isn't one.
   // Used primarily to clear the cache and for getting debug information.
   virtual HostCache* GetHostCache();
 
   // Returns the current DNS configuration |this| is using, as a Value, or NULL
   // if it's configured to always use the system host resolver.  Caller takes
   // ownership of the returned Value.
@@ skipping 12 matching lines @@
  protected:
   HostResolver();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HostResolver);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_HOST_RESOLVER_H_