Add a modal confirmation dialog to the enterprise profile sign-in flow.

chrome/browser/resources/profile_signin_confirmation.js

+cr.define('profile_signin_confirmation', function() {
+  'use strict';
+
+  function initialize() {
+    var args = JSON.parse(chrome.getVariableValue('dialogArguments'));
+    $('dialogMessage').textContent = loadTimeData.getStringF(
+        'dialogMessage', args.username);
+    $('dialogPrompt').textContent = loadTimeData.getStringF(
+        'dialogPrompt', args.username);
+    $('createButton').addEventListener('click', function() {
+      chrome.send('createNewProfile');
+    });
+    $('continueButton').addEventListener('click', function() {
+      chrome.send('continue');
+    });
+    $('cancelButton').addEventListener('click', function() {
+      chrome.send('cancel');
+    });
+  }
+
+  return {
+    initialize: initialize
+  };
+});
+
+document.addEventListener('DOMContentLoaded',
+                          profile_signin_confirmation.initialize);