About page should not automatically trigger OS updates

chrome/browser/resources/help/help_page.js

 // Copyright 2014 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('help', function() {
   var Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
 
   /**
    * Encapsulated handling of the About page. Called 'help' internally to avoid
@@ skipping 89 matching lines @@
 
       var self = this;
       var channelChanger = $('channel-changer');
       if (channelChanger) {
         channelChanger.onchange = function(event) {
           self.setChannel_(event.target.value, false);
         };
       }
 
       if (cr.isChromeOS) {
+        // Add event listener for the check for and apply updates button.
+        this.maybeSetOnClick_($('request-update'), function() {
+          self.setUpdateStatus_('checking');
+          $('request-update').disabled = true;
+          chrome.send('requestUpdate');
+        });
+
         // Add event listener for the close button when shown as an overlay.
         if ($('about-done')) {
           $('about-done').addEventListener('click', function() {
             PageManager.closeOverlay();
           });
         }
 
         $('change-channel').onclick = function() {
           PageManager.showPageByName('channel-change-page', false);
         };
@@ skipping 149 matching lines @@
       var relaunchAndPowerwashHidden = true;
       if ($('relaunch-and-powerwash')) {
         // It's allowed to do powerwash only for customer devices,
         // when user explicitly decides to update to a more stable
         // channel.
         relaunchAndPowerwashHidden =
             !this.powerwashAfterUpdate_ || status != 'nearly_updated';
         $('relaunch-and-powerwash').hidden = relaunchAndPowerwashHidden;
       }
 
+      if (cr.isChromeOS) {
+        // Only enable the update button if it hasn't been used yet or the
+        // status isn't 'updated'.
+        if (!$('request-update').disabled || status != 'updated') {
+          // Disable the button if an update is already in progress.
+          $('request-update').disabled =
+            ['checking', 'updating', 'nearly_updated'].indexOf(status) > -1;
+        }
+      }
+
       var container = $('update-status-container');
       if (container) {
         container.hidden = status == 'disabled';
         $('relaunch').hidden =
             (status != 'nearly_updated') || !relaunchAndPowerwashHidden;
 
+        if (cr.isChromeOS) {
+          // Assume the "updated" status is stale if we haven't checked yet.
+          if (status == 'updated' && !$('request-update').disabled)
+            container.hidden = true;
+
+          // Hide the request update button if auto-updating is disabled or
+          // a relaunch button is showing.
+          $('request-update').hidden = status == 'disabled' ||
+            !$('relaunch').hidden || !relaunchAndPowerwashHidden;
+        }
+
         if (!cr.isMac)
           $('update-percentage').hidden = status != 'updating';
       }
     },
 
     /**
      * @param {number} progress The percent completion.
      * @private
      */
     setProgress_: function(progress) {
@@ skipping 232 matching lines @@
 
   HelpPage.updateChannelChangePageContainerVisibility = function() {
     HelpPage.getInstance().updateChannelChangePageContainerVisibility_();
   };
 
   // Export
   return {
     HelpPage: HelpPage
   };
 });