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

net/http/http_network_transaction_unittest.cc

Index: net/http/http_network_transaction_unittest.cc
===================================================================
--- net/http/http_network_transaction_unittest.cc	(revision 120359)
+++ net/http/http_network_transaction_unittest.cc	(working copy)
@@ -4263,7 +4263,7 @@
   // will need to be unescaped by HttpNetworkTransaction.
   EXPECT_EQ("b%40r", request.url.password());
 
-  request.load_flags = LOAD_NORMAL;
+  request.load_flags = LOAD_NORMAL | LOAD_ENABLE_EMBEDDED_IDENTITY;
 
   MockWrite data_writes1[] = {
     MockWrite("GET / HTTP/1.1\r\n"
@@ -4337,9 +4337,8 @@
   // Note: the URL has a username:password in it.  The password "baz" is
   // wrong (should be "bar").
   request.url = GURL("http://foo:baz@www.google.com/");
+  request.load_flags = LOAD_NORMAL | LOAD_ENABLE_EMBEDDED_IDENTITY;
 
-  request.load_flags = LOAD_NORMAL;
-
   SessionDependencies session_deps;
   scoped_ptr<HttpTransaction> trans(
       new HttpNetworkTransaction(CreateSession(&session_deps)));