diff options
Diffstat (limited to 'chrome')
| -rw-r--r-- | chrome/browser/io_thread.cc | 61 |
1 files changed, 33 insertions, 28 deletions
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc index 2ea8195..d2ce04e 100644 --- a/chrome/browser/io_thread.cc +++ b/chrome/browser/io_thread.cc @@ -27,44 +27,49 @@ namespace { net::HostResolver* CreateGlobalHostResolver( net::NetworkChangeNotifier* network_change_notifier) { - net::HostResolver* global_host_resolver = NULL; - const CommandLine& command_line = *CommandLine::ForCurrentProcess(); - - global_host_resolver = + net::HostResolver* global_host_resolver = net::CreateSystemHostResolver(network_change_notifier); + // Determine if we should disable IPv6 support. if (!command_line.HasSwitch(switches::kEnableIPv6)) { - // Measure impact of allowing IPv6 support without probing. - const FieldTrial::Probability kDivisor = 100; - const FieldTrial::Probability kProbability = 50; // 50% probability. - FieldTrial* trial = new FieldTrial("IPv6_Probe", kDivisor); - int skip_group = trial->AppendGroup("_IPv6_probe_skipped", kProbability); - trial->AppendGroup("_IPv6_probe_done", - FieldTrial::kAllRemainingProbability); - bool use_ipv6_probe = (trial->group() != skip_group); - - // Perform probe, and then optionally use result to disable IPv6. - // Some users report confused OS handling of IPv6, leading to large - // latency. If we can show that IPv6 is not supported, then disabliing it - // will work around such problems. - if ((!net::IPv6Supported() && use_ipv6_probe) || - command_line.HasSwitch(switches::kDisableIPv6)) + if (command_line.HasSwitch(switches::kDisableIPv6)) { global_host_resolver->SetDefaultAddressFamily(net::ADDRESS_FAMILY_IPV4); + } else { + net::HostResolverImpl* host_resolver_impl = + global_host_resolver->GetAsHostResolverImpl(); + if (host_resolver_impl != NULL) { + // (optionally) Use probe to decide if support is warranted. + + // Measure impact of probing to allow IPv6. + // Some users report confused OS handling of IPv6, leading to large + // latency. If we can show that IPv6 is not supported, then disabliing + // it will work around such problems. + const FieldTrial::Probability kDivisor = 100; + const FieldTrial::Probability kProbability = 50; // 50% probability. + FieldTrial* trial = new FieldTrial("IPv6_Probe", kDivisor); + int skip_group = trial->AppendGroup("_IPv6_probe_skipped", + kProbability); + trial->AppendGroup("_IPv6_probe_done", + FieldTrial::kAllRemainingProbability); + bool use_ipv6_probe = (trial->group() != skip_group); + if (use_ipv6_probe) + host_resolver_impl->ProbeIPv6Support(); + } + } } // If hostname remappings were specified on the command-line, layer these // rules on top of the real host resolver. This allows forwarding all requests // through a designated test server. - if (command_line.HasSwitch(switches::kHostResolverRules)) { - net::MappedHostResolver* remapped_resolver = - new net::MappedHostResolver(global_host_resolver); - global_host_resolver = remapped_resolver; - remapped_resolver->SetRulesFromString( - command_line.GetSwitchValueASCII(switches::kHostResolverRules)); - } - - return global_host_resolver; + if (!command_line.HasSwitch(switches::kHostResolverRules)) + return global_host_resolver; + + net::MappedHostResolver* remapped_resolver = + new net::MappedHostResolver(global_host_resolver); + remapped_resolver->SetRulesFromString( + command_line.GetSwitchValueASCII(switches::kHostResolverRules)); + return remapped_resolver; } } // namespace |