Add an Accounts in Token Service section to about:signin-internals.

chrome/browser/resources/signin_internals/signin_internals.js

 // 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.
 
 var chrome = chrome || {};
 
 /**
  * Organizes all signin event listeners and asynchronous requests.
  * This object has no public constructor.
  * @type {Object}
@@ skipping 150 matching lines @@
   chrome.signin[signinFunction] = makeSigninFunction(signinFunction);
 }
 
 chrome.signin.internalsInfo = {};
 
 // Replace the displayed values with the latest fetched ones.
 function refreshSigninInfo(signinInfo) {
   chrome.signin.internalsInfo = signinInfo;
   jstProcess(new JsEvalContext(signinInfo), $('signin-info'));
   jstProcess(new JsEvalContext(signinInfo), $('token-info'));
+  jstProcess(new JsEvalContext(signinInfo), $('account-info'));
 }
 
 // Replace the cookie information with the fetched values.
 function updateCookieAccounts(cookieAccountsInfo) {
   jstProcess(new JsEvalContext(cookieAccountsInfo), $('cookie-info'));
 }
 
 // On load, do an initial refresh and register refreshSigninInfo to be invoked
 // whenever we get new signin information from SigninInternalsUI.
 function onLoad() {
   chrome.signin.getSigninInfo(refreshSigninInfo);
 
   chrome.signin.onSigninInfoChanged.addListener(refreshSigninInfo);
   chrome.signin.onCookieAccountsFetched.addListener(updateCookieAccounts);
 }
 
 document.addEventListener('DOMContentLoaded', onLoad, false);
 })();