[net] Move DnsConfigService to NetworkChangeNotifier.

net/dns/dns_config_service.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/dns_config_service.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/values.h"
 #include "net/base/ip_endpoint.h"
@@ skipping 63 matching lines @@
 }
 
 
 DnsConfigService::DnsConfigService()
     : have_config_(false),
       have_hosts_(false),
       need_update_(false),
       last_sent_empty_(true) {}
 
 DnsConfigService::~DnsConfigService() {
-  // Must always clean up.
-  NetworkChangeNotifier::RemoveDNSObserver(this);
 }
 
-void DnsConfigService::Read(const CallbackType& callback) {
+void DnsConfigService::ReadConfig(const CallbackType& callback) {
   DCHECK(CalledOnValidThread());
   DCHECK(!callback.is_null());
   DCHECK(callback_.is_null());
   callback_ = callback;
-  OnDNSChanged(NetworkChangeNotifier::CHANGE_DNS_WATCH_STARTED);
+  this->ReadNow();
 }
 
-void DnsConfigService::Watch(const CallbackType& callback) {
+void DnsConfigService::WatchConfig(const CallbackType& callback) {
   DCHECK(CalledOnValidThread());
   DCHECK(!callback.is_null());
   DCHECK(callback_.is_null());
-  NetworkChangeNotifier::AddDNSObserver(this);
   callback_ = callback;
-  if (NetworkChangeNotifier::IsWatchingDNS())
-    OnDNSChanged(NetworkChangeNotifier::CHANGE_DNS_WATCH_STARTED);
-  // else: Wait until signal before reading.
+  this->StartWatching();

[pauljensen, 2012/08/27 21:44:10]

|StartWatching|'s return value is never used...doesn't really matter; I guess it
just allows future use.

[szym, 2012/08/27 21:49:20]

Right. http://crbug.com/116139. I guess I should figure out how to measure how
often the watchers actually fail.

+  this->ReadNow();
 }
 
 void DnsConfigService::InvalidateConfig() {
   DCHECK(CalledOnValidThread());
   base::TimeTicks now = base::TimeTicks::Now();
   if (!last_invalidate_config_time_.is_null()) {
     UMA_HISTOGRAM_LONG_TIMES("AsyncDNS.ConfigNotifyInterval",
                              now - last_invalidate_config_time_);
   }
   last_invalidate_config_time_ = now;
@@ skipping 99 matching lines @@
   timer_.Stop();
   if (!need_update_)
     return;
   need_update_ = false;
   last_sent_empty_ = false;
   callback_.Run(dns_config_);
 }
 
 }  // namespace net