rem: return Components.classes["@mozilla.org/preferences;1"] .getService(Components.interfaces.nsIPref); 
add: return Components.classes["@mozilla.org/preferences-service;1"] .getService(Components.interfaces.nsIPrefBranch); 
context:   get mPrefService()    {      return Components.classes["@mozilla.org/preferences;1"]                       .getService(Components.interfaces.nsIPref);    },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/faf03ce445712b372523f881cc3144cfadc7a611/nsUserSettings.js/buggy/xpfe/global/resources/content/nsUserSettings.js