Issue 1594 - Handle missing userInfo when processing contextmenu events on Safari

safari/ext/background.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 235 matching lines @@
       items.push(item);
     },
     removeAll: function()
     {
       contextMenuItems.delete(this._page);
     }
   };
 
   safari.application.addEventListener("contextmenu", function(event)
   {
+    if (!event.userInfo)
+      return;
+
     var pageId = event.userInfo.pageId;
     if (!pageId)
       return;
 
     var page = pages[event.userInfo.pageId];
     var items = contextMenuItems.get(page);
     if (!items)
       return;
 
     var context = event.userInfo.tagName;
@@ skipping 403 matching lines @@
         page.activate();
         if (callback)
           callback(page);
         return;
       }
     }
 
     ext.pages.open(optionsUrl, callback);
   };
 })();