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

net/url_request/url_request_unittest.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 "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <shlobj.h>
 #include <windows.h>
 #endif
@@ skipping 2436 matching lines @@
     TestNetworkDelegate network_delegate;  // must outlive URLRequest
     scoped_refptr<TestURLRequestContext> context(
         new TestURLRequestContext(true));
     context->set_network_delegate(&network_delegate);
     context->Init();
 
     TestDelegate d;
     d.set_credentials(AuthCredentials(kUser, kSecret));
 
     URLRequest r(url_requiring_auth, &d);
+    r.set_load_flags(LOAD_NORMAL | LOAD_ENABLE_EMBEDDED_IDENTITY);
     r.set_context(context);
     r.Start();
 
     MessageLoop::current()->Run();
 
     EXPECT_TRUE(d.data_received().find("user/secret") != std::string::npos);
 
     // Make sure we sent the cookie in the restarted transaction.
     EXPECT_TRUE(d.data_received().find("Cookie: got_challenged=true")
         != std::string::npos);
@@ skipping 11 matching lines @@
     TestDelegate d;
 
     GURL::Replacements replacements;
     std::string username("user2");
     std::string password("secret");
     replacements.SetUsernameStr(username);
     replacements.SetPasswordStr(password);
     GURL url_with_identity = url_requiring_auth.ReplaceComponents(replacements);
 
     URLRequest r(url_with_identity, &d);
+    r.set_load_flags(LOAD_NORMAL | LOAD_ENABLE_EMBEDDED_IDENTITY);
     r.set_context(context);
     r.Start();
 
     MessageLoop::current()->Run();
 
     EXPECT_TRUE(d.data_received().find("user2/secret") != std::string::npos);
 
     // Make sure we sent the cookie in the restarted transaction.
     EXPECT_TRUE(d.data_received().find("Cookie: got_challenged=true")
         != std::string::npos);
@@ skipping 1581 matching lines @@
   req.SetExtraRequestHeaders(headers);
   req.Start();
   MessageLoop::current()->Run();
   // If the net tests are being run with ChromeFrame then we need to allow for
   // the 'chromeframe' suffix which is added to the user agent before the
   // closing parentheses.
   EXPECT_TRUE(StartsWithASCII(d.data_received(), "Lynx (textmode", true));
 }
 
 }  // namespace net