Turn off ipv6 when there is no support at startup....

net/base/host_resolver_proc.cc

 // Copyright (c) 2010 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_proc.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 #include <resolv.h>
@@ skipping 209 matching lines @@
   }
 #endif
 
   if (err)
     return ERR_NAME_NOT_RESOLVED;
 
   addrlist->Adopt(ai);
   return OK;
 }
 
+// TODO(jar): The following is a simple estimate of ipv6 support.  We may need
+// to do a test resolution, and a test connection, to REALLY verify support.
+// static
+bool HostResolverProc::IPv6Supported() {
+#if defined(OS_POSIX)
+  int test_socket;
+#else
+  SOCKET test_socket;
+#endif
+
+  test_socket = socket(AF_INET6, SOCK_STREAM, 0);
+  if (test_socket == -1)
+    return false;
+
+#if defined(OS_POSIX)
+  close(test_socket);
+#else
+  closesocket(test_socket);
+#endif
+
+  return true;
+}
+
 }  // namespace net