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) {
+          // Hide the status container if we haven't checked for updates yet.

[deymo, 2014/08/19 05:09:12]

This comment isn't quite accurate. We want to show the status of the current
update even if we didn't initiate it. Example:

Check for update, update is in progress (i.e. 20% done), refresh page --> update
should show progress.

Also, if you open this page to see if there's an update in progress you should
see that. It looks like the code is right but the comment is not.

[michaelpg, 2014/08/19 05:20:02]

I agree -- this is the desired behavior and what the code does. I'll update the
comment.

+          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
   };
 });