Adapted private browsing handling to per-window private browsing in Firefox 20

lib/filterStorage.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 711 matching lines @@
    */
   enabled: false,
 
   /**
    * Checks whether private browsing is enabled for a particular window.
    */
   enabledForWindow: function(/**Window*/ wnd) /**Boolean*/
   {
     try
     {
-      let loadContext = wnd.QueryInterface(Ci.nsIInterfaceRequestor)
-                           .getInterface(Ci.nsILoadContext);
-      if ("usePrivateBrowsing" in loadContext)
-        return loadContext.usePrivateBrowsing;
-      else
-        return false;   // Gecko 12 or below
-    }
-    catch(e)
-    {
-      Cu.reportError(e);
+      return wnd.QueryInterface(Ci.nsIInterfaceRequestor)
+                .getInterface(Ci.nsILoadContext)
+                .usePrivateBrowsing;
+    }
+    catch (e)
+    {
+      // Gecko 19 and below will throw NS_NOINTERFACE, this is expected
+      if (e.result != Cr.NS_NOINTERFACE)
+        Cu.reportError(e);
       return false;
     }
   },
 
   init: function()
   {
     if ("@mozilla.org/privatebrowsing;1" in Cc)
     {
       try
       {
@@ skipping 121 matching lines @@
       else if (this.wantObj === false && val)
         this.curObj.push(val.replace(/\\\[/g, "["));
     }
     finally
     {
       Filter.knownFilters = origKnownFilters;
       Subscription.knownSubscriptions = origKnownSubscriptions;
     }
   }
 };