It seems GAIA had changed dosserver rules today, so we can go back to accounts.google.com.

chrome/common/net/gaia/gaia_urls.h

 // 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.
 
 #ifndef CHROME_COMMON_NET_GAIA_GAIA_URLS_H_
 #define CHROME_COMMON_NET_GAIA_GAIA_URLS_H_
 #pragma once
 
 #include <string>
 
 #include "base/memory/singleton.h"
 
 // A signleton that provides all the URLs that are used for connecting to GAIA.
 class GaiaUrls {
  public:
   static GaiaUrls* GetInstance();
 
   // The URLs for different calls in the Google Accounts programmatic login API.
   const std::string& captcha_url_prefix();
 
   const std::string& gaia_origin_url();
   const std::string& client_login_url();
+  const std::string& service_login_url();
   const std::string& issue_auth_token_url();
   const std::string& get_user_info_url();
   const std::string& token_auth_url();
   const std::string& merge_session_url();
   const std::string& get_oauth_token_url();
   const std::string& oauth_get_access_token_url();
   const std::string& oauth_wrap_bridge_url();
   const std::string& oauth_user_info_url();
   const std::string& oauth_revoke_token_url();
   const std::string& oauth1_login_url();
@@ skipping 13 matching lines @@
  private:
   GaiaUrls();
   ~GaiaUrls();
 
   friend struct DefaultSingletonTraits<GaiaUrls>;
 
   std::string captcha_url_prefix_;
 
   std::string gaia_origin_url_;
   std::string client_login_url_;
+  std::string service_login_url_;
   std::string issue_auth_token_url_;
   std::string get_user_info_url_;
   std::string token_auth_url_;
   std::string merge_session_url_;
   std::string get_oauth_token_url_;
   std::string oauth_get_access_token_url_;
   std::string oauth_wrap_bridge_url_;
   std::string oauth_user_info_url_;
   std::string oauth_revoke_token_url_;
   std::string oauth1_login_url_;
 
   std::string oauth1_login_scope_;
   std::string oauth_wrap_bridge_user_info_scope_;
   std::string client_oauth_url_;
 
   std::string oauth2_chrome_client_id_;
   std::string oauth2_chrome_client_secret_;
   std::string client_login_to_oauth2_url_;
   std::string oauth2_token_url_;
   std::string oauth2_issue_token_url_;
 
   std::string gaia_login_form_realm_;
 
   DISALLOW_COPY_AND_ASSIGN(GaiaUrls);
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_GAIA_URLS_H_