Don't use IDENT_SRC_URL for HttpAuth challenges. IE hasn't supported it for years, and at worst ...

net/http/http_proxy_utils.cc

 // 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.
 
 #include "net/http/http_proxy_utils.h"
 
 #include "base/stringprintf.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/net_errors.h"
@@ skipping 26 matching lines @@
                                             &user_agent))
     request_headers->SetHeader(HttpRequestHeaders::kUserAgent, user_agent);
 
   request_headers->MergeFrom(auth_headers);
 }
 
 int HandleAuthChallenge(HttpAuthController* auth,
                         HttpResponseInfo* response,
                         const BoundNetLog& net_log) {
   DCHECK(response->headers);
+  int option_mask = (HttpAuthController::CHALLENGE_OPTION_SEND_SERVER_AUTH |
+                     HttpAuthController::CHALLENGE_OPTION_USE_EMBEDDED_AUTH |

[cbentzel, 2012/02/06 15:55:38]

Why is embedded auth OK here? 

[Tom Sepez, 2012/02/06 18:05:30]

Duplicating the existing logic in this path.  Was only concerned with changing
the other caller.

+                     HttpAuthController::CHALLENGE_OPTION_ESTABLISHING_TUNNEL);
 
-  int rv = auth->HandleAuthChallenge(response->headers, false, true, net_log);
+  int rv = auth->HandleAuthChallenge(response->headers, option_mask, net_log);
   response->auth_challenge = auth->auth_info();
   if (rv == OK)
     return ERR_PROXY_AUTH_REQUESTED;
   return rv;
 }
 
 }  // namespace net