Fix layout of the sync and sign-in error dialogs when the page zoom is increased.

chrome/browser/resources/signin/sync_confirmation/sync_confirmation.js

 /* Copyright 2015 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. */
 
 cr.define('sync.confirmation', function() {
   'use strict';
 
   function onConfirm(e) {
     chrome.send('confirm');
   }
@@ skipping 10 matching lines @@
     document.addEventListener('keydown', onKeyDown);
     $('confirmButton').addEventListener('click', onConfirm);
     $('undoButton').addEventListener('click', onUndo);
     if (loadTimeData.getBoolean('isSyncAllowed')) {
       $('settingsLink').addEventListener('click', onGoToSettings);
       $('profile-picture').addEventListener('load', onPictureLoaded);
       $('syncDisabledDetails').hidden = true;
     } else {
       $('syncConfirmationDetails').hidden = true;
     }
-    chrome.send('initializedWithSize', [document.body.scrollHeight]);
+
+    // Prefer using |document.body.offsetHeight| instead of
+    // |document.body.scrollHeight| as it returns the correct height of the
+    // even when the page zoom in Chrome is different than 100%.
+    chrome.send('initializedWithSize', [document.body.offsetHeight]);
   }
 
   function clearFocus() {
     document.activeElement.blur();
   }
 
   function setUserImageURL(url) {
     if (loadTimeData.getBoolean('isSyncAllowed')) {
       $('profile-picture').src = url;
     }
@@ skipping 17 matching lines @@
   }
 
   return {
     clearFocus: clearFocus,
     initialize: initialize,
     setUserImageURL: setUserImageURL
   };
 });
 
 document.addEventListener('DOMContentLoaded', sync.confirmation.initialize);