issue #764 - Adblock Warning opt in message isn't triggered

lib/ui.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 1869 matching lines @@
 
       insertMessage(element, after, links);
     }
 
     let texts = Notification.getLocalizedTexts(notification);
     let titleElement = window.document.getElementById("abp-notification-title");
     titleElement.textContent = texts.title;
     let messageElement = window.document.getElementById("abp-notification-message");
     messageElement.innerHTML = "";
     let docLinks = [];
-    for (let link of notification.links)
-      docLinks.push(Utils.getDocLink(link));
+    if (notification.links)
+      for (let link of notification.links)
+        docLinks.push(Utils.getDocLink(link));
+
     insertMessage(messageElement, texts.message, docLinks);
 
     messageElement.addEventListener("click", function(event)
     {
       let link = event.target;
       while (link && link !== messageElement && link.localName !== "a")
         link = link.parentNode;
       if (!link || link.localName !== "a")
         return;
       event.preventDefault();
@@ skipping 46 matching lines @@
   ["abp-command-contribute", "command", UI.openContributePage.bind(UI)],
   ["abp-command-contribute-hide", "command", UI.hideContributeButton.bind(UI)]
 ];
 
 onShutdown.add(function()
 {
   for (let window in UI.applicationWindows)
     if (UI.isBottombarOpen(window))
       UI.toggleBottombar(window);
 });