Disable IPv6 results for the PAC bindings:...

net/proxy/proxy_resolver_js_bindings.cc

 // Copyright (c) 2009 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/proxy/proxy_resolver_js_bindings.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/waitable_event.h"
@@ skipping 14 matching lines @@
   SyncHostResolverBridge(HostResolver* host_resolver,
                          MessageLoop* host_resolver_loop)
       : host_resolver_(host_resolver),
         host_resolver_loop_(host_resolver_loop),
         event_(false, false),
         ALLOW_THIS_IN_INITIALIZER_LIST(
             callback_(this, &SyncHostResolverBridge::OnResolveCompletion)) {
   }
 
   // Run the resolve on host_resolver_loop, and wait for result.
-  int Resolve(const std::string& hostname, net::AddressList* addresses) {
+  int Resolve(const std::string& hostname,
+              AddressFamily address_family,
+              net::AddressList* addresses) {
     // Port number doesn't matter.
     HostResolver::RequestInfo info(hostname, 80);
+    info.set_address_family(address_family);
 
     // Hack for tests -- run synchronously on current thread.
     if (!host_resolver_loop_)
       return host_resolver_->Resolve(info, addresses, NULL, NULL, NULL);
 
     // Otherwise start an async resolve on the resolver's thread.
     host_resolver_loop_->PostTask(FROM_HERE, NewRunnableMethod(this,
         &SyncHostResolverBridge::StartResolve, info, addresses));
 
     // Wait for the resolve to complete in the resolver's thread.
@@ skipping 52 matching lines @@
   }
 
   // Handler for "dnsResolve(host)". Returns empty string on failure.
   virtual std::string DnsResolve(const std::string& host) {
     // TODO(eroman): Should this return our IP address, or fail, or
     // simply be unspecified (works differently on windows and mac os x).
     if (host.empty())
       return std::string();
 
     // Do a sync resolve of the hostname.
+    // Disable IPv6 results, see http://crbug.com/24641 for motivation.

[wtc, 2009/10/22 21:53:54]

The motivation is short (dnsResolve is IPv4 only).  I'd just
state it here rather than forcing the reader to read a long
bug report.

     net::AddressList address_list;
-    int result = host_resolver_->Resolve(host, &address_list);
+    int result = host_resolver_->Resolve(host,
+                                         ADDRESS_FAMILY_IPV4_ONLY,

[wtc, 2009/10/22 21:53:54]

Nit: do we really need _ONLY in the enum constant name?

Except for ADDRESS_FAMILY_UNSPECIFIED, all the
ADDRESS_FAMILY_ enum constants specify a single address
family.  So _ONLY is implied.

+                                         &address_list);
 
     if (result != OK)
       return std::string();  // Failed.
 
     if (!address_list.head())
       return std::string();
 
     // There may be multiple results; we will just use the first one.
     // This returns empty string on failure.
     return net::NetAddressToString(address_list.head());
@@ skipping 13 matching lines @@
 
 }  // namespace
 
 // static
 ProxyResolverJSBindings* ProxyResolverJSBindings::CreateDefault(
     HostResolver* host_resolver, MessageLoop* host_resolver_loop) {
   return new DefaultJSBindings(host_resolver, host_resolver_loop);
 }
 
 }  // namespace net