Get rid of nested functions declarations that are not on top level (causes strict mode warnings)

lib/ui.js

 /*
  * This file is part of the Adblock Plus,
  * Copyright (C) 2006-2012 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 1698 matching lines @@
     if (wnd.frameElement)
     {
       let data = RequestNotifier.getDataForNode(wnd.frameElement, true);
       if (data && !data[1].filter)
         addMenuItem(data);
     }
 
     // Look for a background image
     if (!hadImage)
     {
-      function extractImageURL(computedStyle, property)
+      let extractImageURL = function(computedStyle, property)
       {
         let value = computedStyle.getPropertyCSSValue(property);
         // CSSValueList
         if ("length" in value && value.length >= 1)
           value = value[0];
         // CSSValuePrimitiveType
         if ("primitiveType" in value && value.primitiveType == value.CSS_URI)
           return Utils.unwrapURL(value.getStringValue()).spec;
 
         return null;
-      }
+      };
 
       let node = target;
       while (node)
       {
         if (node.nodeType == Ci.nsIDOMNode.ELEMENT_NODE)
         {
           let style = wnd.getComputedStyle(node, "");
           let bgImage = extractImageURL(style, "background-image") || extractImageURL(style, "list-style-image");
           if (bgImage)
           {
@@ skipping 189 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);
 });