[net/dns] Instrument DnsConfigService to measure performance and failures.

net/dns/dns_config_service_win.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_DNS_CONFIG_SERVICE_WIN_H_
 #define NET_DNS_DNS_CONFIG_SERVICE_WIN_H_
 #pragma once
 
 // The sole purpose of dns_config_service_win.h is for unittests so we just
 // include these headers here.
@@ skipping 83 matching lines @@
   DevolutionSetting policy_devolution;
   // SYSTEM\CurrentControlSet\Dnscache\Parameters
   DevolutionSetting dnscache_devolution;
   // SYSTEM\CurrentControlSet\Tcpip\Parameters
   DevolutionSetting tcpip_devolution;
 
   // SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\AppendToMultiLabelName
   RegDword append_to_multi_label_name;
 };
 
+enum ConfigParseWinResult {
+  CONFIG_PARSE_WIN_OK = 0,
+  CONFIG_PARSE_WIN_READ_IPHELPER,
+  CONFIG_PARSE_WIN_READ_POLICY_SEARCHLIST,
+  CONFIG_PARSE_WIN_READ_TCPIP_SEARCHLIST,
+  CONFIG_PARSE_WIN_READ_DOMAIN,
+  CONFIG_PARSE_WIN_READ_POLICY_DEVOLUTION,
+  CONFIG_PARSE_WIN_READ_DNSCACHE_DEVOLUTION,
+  CONFIG_PARSE_WIN_READ_TCPIP_DEVOLUTION,
+  CONFIG_PARSE_WIN_READ_APPEND_MULTILABEL,
+  CONFIG_PARSE_WIN_READ_PRIMARY_SUFFIX,
+  CONFIG_PARSE_WIN_BAD_ADDRESS,
+  CONFIG_PARSE_WIN_NO_NAMESERVERS,
+  CONFIG_PARSE_WIN_MAX  // Bounding values for enumeration.
+};
+
 // Fills in |dns_config| from |settings|. Exposed for tests.
-bool NET_EXPORT_PRIVATE ConvertSettingsToDnsConfig(
+ConfigParseWinResult NET_EXPORT_PRIVATE ConvertSettingsToDnsConfig(
     const DnsSystemSettings& settings,
     DnsConfig* dns_config);
 
 // Use DnsConfigService::CreateSystemService to use it outside of tests.
 class NET_EXPORT_PRIVATE DnsConfigServiceWin
     : public DnsConfigService,
       public NetworkChangeNotifier::IPAddressObserver {
  public:
   DnsConfigServiceWin();
   virtual ~DnsConfigServiceWin();
@@ skipping 15 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(DnsConfigServiceWin);
 };
 
 }  // namespace internal
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_CONFIG_SERVICE_WIN_H_