This fixes a bug I introduced last night

net/base/x509_certificate_nss.cc

 // Copyright (c) 2011 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/x509_certificate.h"
 
 #include <cert.h>
 #include <cryptohi.h>
 #include <keyhi.h>
 #include <nss.h>
@@ skipping 692 matching lines @@
     cert->default_nickname_ = nickname;
 
   return cert;
 }
 
 std::string X509Certificate::GetDefaultNickname(CertType type) const {
   if (!default_nickname_.empty())
     return default_nickname_;
 
   std::string result;
-  if (type == USER_CERT) {
+  if (type == USER_CERT && cert_handle_->slot) {
     // Find the private key for this certificate and see if it has a
     // nickname.  If there is a private key, and it has a nickname, then
     // we return that nickname.
     SECKEYPrivateKey* private_key = PK11_FindPrivateKeyFromCert(
         cert_handle_->slot,
         cert_handle_,
         NULL);  // wincx
     if (private_key) {
       char* private_key_nickname = PK11_GetPrivateKeyNickname(private_key);
       if (private_key_nickname) {
@@ skipping 412 matching lines @@
 
 // static
 bool X509Certificate::WriteOSCertHandleToPickle(OSCertHandle cert_handle,
                                                 Pickle* pickle) {
   return pickle->WriteData(
       reinterpret_cast<const char*>(cert_handle->derCert.data),
       cert_handle->derCert.len);
 }
 
 }  // namespace net