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

Index: net/http/http_proxy_utils.cc
===================================================================
--- net/http/http_proxy_utils.cc	(revision 120359)
+++ net/http/http_proxy_utils.cc	(working copy)
@@ -44,8 +44,11 @@
                         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;