[net/dns] Only record HaveDnsChanged if the nameserver is not INADDR_ANY.

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 1415 matching lines @@
 
     net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HOST_RESOLVER_IMPL_JOB,
                                       net_error);
 
     DCHECK(!requests_.empty());
 
     if (net_error == OK) {
       SetPortOnAddressList(requests_->front()->info().port(), &list);
       // Record this histogram here, when we know the system has a valid DNS
       // configuration.
-      UMA_HISTOGRAM_ENUMERATION("AsyncDNS.HaveDnsConfig",
-                                resolver_->received_dns_config_ ? 1 : 0,
-                                2);
+      UMA_HISTOGRAM_BOOLEAN("AsyncDNS.HaveDnsConfig",
+                            resolver_->received_dns_config_);
     }
 
     if ((net_error != ERR_ABORTED) &&
         (net_error != ERR_HOST_RESOLVER_QUEUE_TOO_LARGE)) {
       resolver_->CacheResult(key_, net_error, list, ttl);
     }
 
     // Complete all of the requests that were attached to the job.
     for (RequestsList::const_iterator it = requests_.begin();
          it != requests_.end(); ++it) {
@@ skipping 510 matching lines @@
 }
 
 void HostResolverImpl::OnDnsConfigChanged(const DnsConfig& dns_config) {
   if (net_log_) {
     net_log_->AddGlobalEntry(
         NetLog::TYPE_DNS_CONFIG_CHANGED,
         make_scoped_refptr(new DnsConfigParameters(dns_config)));
   }
 
   // TODO(szym): Remove once http://crbug.com/125599 is resolved.
-  received_dns_config_ = dns_config.IsValid();
+  received_dns_config_ = false;
+  if (dns_config.IsValid()) {
+    // Quick check if the address is not INADDR_ANY, which is the default value
+    // in absence of network connection. http://crbug.com/130808
+    if (dns_config.nameservers[0].address()[0]) {

[mmenke, 2012/06/01 22:20:27]

Is it possible that we'd have INADDR_ANY, followed by other addresses?  If not,
LGTM.  If so, might want to check for that.

+      received_dns_config_ = true;
+    }

[mmenke, 2012/06/01 22:20:27]

nit:  No brackets for single-line ifs.

[mmenke, 2012/06/01 22:21:20]

Actually, I'm never sure if that is optional or not...Know it's been discussed
before.  Erm...I really don't care.

[mmenke, 2012/06/01 22:24:14]

Ahh, chromium style guide:

Other formatting "rules" are not required, but are fairly common across Chrome
code, and thus it's probably best to stick to them unless you have a reason not
to.  In particular, if existing code follows these styles, maintain them:
* Prefer (foo == 0) to (0 == foo)
* Omit {} for conditional or loop bodies where the body is just one physical
line.  Otherwise, use {}.
* Function declaration order should match function definition order

+  }
 
   // Life check to bail once |this| is deleted.
   base::WeakPtr<HostResolverImpl> self = AsWeakPtr();
 
   if (dns_client_.get()) {
     // We want a new factory in place, before we Abort running Jobs, so that the
     // newly started jobs use the new factory.
     dns_client_->SetConfig(dns_config);
     OnDNSChanged(NetworkChangeNotifier::CHANGE_DNS_SETTINGS);
     // |this| may be deleted inside OnDNSChanged().
     if (self)
       TryServingAllJobsFromHosts();
   }
 }
 
 bool HostResolverImpl::HaveDnsConfig() const {
   return (dns_client_.get() != NULL) && (dns_client_->GetConfig() != NULL);
 }
 
 }  // namespace net