Remove measurement of DNS resolution waste from not always performing AF_UNSPEC

net/base/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/base/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 1707 matching lines @@
     RecordTotalTime(HaveDnsConfig(), info.is_speculative(), base::TimeDelta());
     return rv;
   }
 
   // Next we need to attach our request to a "job". This job is responsible for
   // calling "getaddrinfo(hostname)" on a worker thread.
 
   JobMap::iterator jobit = jobs_.find(key);
   Job* job;
   if (jobit == jobs_.end()) {
-    // If we couldn't find the desired address family, check to see if the
-    // other family is in the cache or another job, which indicates waste,
-    // and we should fix crbug.com/139811.
-    {
-      bool ipv4 = key.address_family == ADDRESS_FAMILY_IPV4;
-      Key other_family_key = key;
-      other_family_key.address_family = ipv4 ?
-          ADDRESS_FAMILY_UNSPECIFIED : ADDRESS_FAMILY_IPV4;
-      bool found_other_family_cache = false;
-      bool found_other_family_job = false;
-      if (default_address_family_ == ADDRESS_FAMILY_UNSPECIFIED) {
-        found_other_family_cache = cache_.get() &&
-            cache_->Lookup(other_family_key, base::TimeTicks::Now()) != NULL;
-        if (!found_other_family_cache)
-          found_other_family_job = jobs_.count(other_family_key) > 0;
-      }
-      enum {  // Used in UMA_HISTOGRAM_ENUMERATION.
-        AF_WASTE_IPV4_ONLY,
-        AF_WASTE_CACHE_IPV4,
-        AF_WASTE_CACHE_UNSPEC,
-        AF_WASTE_JOB_IPV4,
-        AF_WASTE_JOB_UNSPEC,
-        AF_WASTE_NONE_IPV4,
-        AF_WASTE_NONE_UNSPEC,
-        AF_WASTE_MAX,  // Bounding value.
-      } category = AF_WASTE_MAX;
-      if (default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED) {
-        category = AF_WASTE_IPV4_ONLY;
-      } else if (found_other_family_cache) {
-        category = ipv4 ? AF_WASTE_CACHE_IPV4 : AF_WASTE_CACHE_UNSPEC;
-      } else if (found_other_family_job) {
-        category = ipv4 ? AF_WASTE_JOB_IPV4 : AF_WASTE_JOB_UNSPEC;
-      } else {
-        category = ipv4 ? AF_WASTE_NONE_IPV4 : AF_WASTE_NONE_UNSPEC;
-      }
-      UMA_HISTOGRAM_ENUMERATION("DNS.ResolveUnspecWaste", category,
-                                AF_WASTE_MAX);
-    }
-
     job = new Job(weak_ptr_factory_.GetWeakPtr(), key, info.priority(),
                   request_net_log);
     job->Schedule();
 
     // Check for queue overflow.
     if (dispatcher_.num_queued_jobs() > max_queued_jobs_) {
       Job* evicted = static_cast<Job*>(dispatcher_.EvictOldestLowest());
       DCHECK(evicted);
       evicted->OnEvicted();  // Deletes |evicted|.
       if (evicted == job) {
@@ skipping 391 matching lines @@
   }
   DnsConfig dns_config;
   NetworkChangeNotifier::GetDnsConfig(&dns_config);
   dns_client_->SetConfig(dns_config);
   num_dns_failures_ = 0;
   if (dns_config.IsValid())
     UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
 }
 
 }  // namespace net