Detect and handle the case of our own typo correction extension being installed in parallel

lib/typoBootstrap.js

 /*
- * 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/.
+ * 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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /**
  * @fileOverview Adds typo correction feature
  */
 
 Cu.import("resource://gre/modules/AddonManager.jsm");
 
 let {Prefs} = require("prefs");
 let urlfixerID = "{0fa2149e-bb2c-4ac2-a8d3-479599819475}";
@@ skipping 16 matching lines @@
       {
         init();
         Prefs.removeListener(onPrefChange);
       }
     }
     
     Prefs.addListener(onPrefChange);
   }
 }
 
-exports.cleanup = cleanup;
-function cleanup()
-{
-  if (addonListener)
-  {
-    AddonManager.removeAddonListener(addonListener);

[Wladimir Palant, 2012/11/20 10:21:14]

Please use onShutdown.add() to add a shutdown handler for that - right after you
add the listener. This is a global thing, not a per-window one. Please look
around for examples.

-    addonListener = null;
-  }
-}
-
 function startTypoCorrection(isInstalledAndEnabled)
 {
   if (isInstalledAndEnabled)
     require("typoFixer").detachWindowObserver();
   else
     require("typoFixer").attachWindowObserver();
   
   if (!addonListener)
   {
     addonListener = {
@@ skipping 13 matching lines @@
           startTypoCorrection(true);
       },
       onUninstalled: function(addon)
       {
         if (addon.id == urlfixerID)
           startTypoCorrection(false);
       }
     }
     
     AddonManager.addAddonListener(addonListener);
+    onShutdown.add(function() AddonManager.removeAddonListener(addonListener));
   }
 }
 
 init();