Issue 3431 - Element Hiding Helper shutdown fails (shutdown is not a function)

chrome/content/actor.jsm

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let EXPORTED_SYMBOLS = ["shutdown", "getNodeInfo", "togglePreview",
                         "forgetNode"];
 
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 let {console} = Cu.import("resource://gre/modules/devtools/Console.jsm", {});
 let {DebuggerServer} = Cu.import("resource://gre/modules/devtools/dbg-server.jsm", {});
 let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
 
 let processID = Services.appinfo.processID;
 let maxNodeID = 0;
 let nodes = new Map();
 
 let name = "elemhidehelper";
 let actor = {
   constructorFun: Actor,
   constructorName: name,
   name: name
 };
 
 DebuggerServer.addTabActor(actor, name);
 
-let shutdown = (function()
+var shutdown = (function()
 {
   let executed = false;
   return function()
   {
     if (!executed)
     {
       executed = true;
       try
       {
         DebuggerServer.removeTabActor(actor);
@@ skipping 121 matching lines @@
       // forget this node then.
       forgetNode(nodeID);
     }
   }
 }
 
 function forgetNode(nodeID)
 {
   nodes.delete(nodeID);
 }