Remove unused Net.IPv6ConnectDuration histogram.

net/dns/host_resolver_impl.cc

 // 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.
 
 #include "net/dns/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 2137 matching lines @@
 }
 
 HostResolverImpl::Key HostResolverImpl::GetEffectiveKeyForRequest(
     const RequestInfo& info, const BoundNetLog& net_log) const {
   HostResolverFlags effective_flags =
       info.host_resolver_flags() | additional_resolver_flags_;
   AddressFamily effective_address_family = info.address_family();
 
   if (info.address_family() == ADDRESS_FAMILY_UNSPECIFIED) {
     if (probe_ipv6_support_ && !use_local_ipv6_) {
-      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));
       BoundNetLog probe_net_log = BoundNetLog::Make(
           net_log.net_log(), NetLog::SOURCE_IPV6_REACHABILITY_CHECK);
       probe_net_log.BeginEvent(NetLog::TYPE_IPV6_REACHABILITY_CHECK,
                                net_log.source().ToEventParametersCallback());
       bool rv6 = IsGloballyReachable(address, probe_net_log);
       probe_net_log.EndEvent(NetLog::TYPE_IPV6_REACHABILITY_CHECK);
       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);
       } 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;
       }
@@ skipping 173 matching lines @@
     dns_client_->SetConfig(dns_config);
     num_dns_failures_ = 0;
     if (dns_client_->GetConfig())
       UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
   }
 
   AbortDnsTasks();
 }
 
 }  // namespace net