webRequest.onAuthRequired listeners can provide authentication credentials.

chrome/browser/extensions/extension_webrequest_apitest.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 "base/command_line.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_webrequest_api.h"
 #include "chrome/browser/ui/login/login_prompt.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_switches.h"
@@ skipping 51 matching lines @@
       switches::kEnableExperimentalExtensionApis);
 
   ASSERT_TRUE(RunExtensionSubtest("webrequest", "test_simple.html")) <<
       message_;
 }
 
 IN_PROC_BROWSER_TEST_F(ExtensionWebRequestApiTest, WebRequestComplex) {
   CommandLine::ForCurrentProcess()->AppendSwitch(
       switches::kEnableExperimentalExtensionApis);
 
-  // Needed for the auth tests.
-  CancelLoginDialog login_dialog_helper;
-
   ASSERT_TRUE(RunExtensionSubtest("webrequest", "test_complex.html")) <<
       message_;
 }
 
+IN_PROC_BROWSER_TEST_F(ExtensionWebRequestApiTest, WebRequestAuthRequired) {
+  CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kEnableExperimentalExtensionApis);
+
+  CancelLoginDialog login_dialog_helper;
+
+  ASSERT_TRUE(RunExtensionSubtest("webrequest", "test_auth_required.html")) <<
+      message_;
+}
+
 // Hangs flakily: http://crbug.com/91715
 IN_PROC_BROWSER_TEST_F(ExtensionWebRequestApiTest,
                        DISABLED_WebRequestBlocking) {
   CommandLine::ForCurrentProcess()->AppendSwitch(
       switches::kEnableExperimentalExtensionApis);
 
   ASSERT_TRUE(RunExtensionSubtest("webrequest", "test_blocking.html")) <<
       message_;
 }