nsLiteralString prefName(someData);
nsDependentString prefName(someData);
NS_IMETHODIMP nsCharsetMenuObserver::Observe(nsISupports *aSubject, const PRUnichar *aTopic, const PRUnichar *someData){  nsresult rv;  nsLiteralString aTopicString(aTopic);  if (aTopicString.Equals(NS_LITERAL_STRING("nsPref:changed"))) {    nsLiteralString prefName(someData);    if (prefName.Equals(NS_LITERAL_STRING(kBrowserStaticPrefKey))) {      // refresh menus which share this pref      rv = mCharsetMenu->RefreshBroserMenu();      NS_ENSURE_SUCCESS(rv, rv);      rv = mCharsetMenu->RefreshMailviewMenu();      NS_ENSURE_SUCCESS(rv, rv);      rv = mCharsetMenu->RefreshComposerMenu();    }    else if (prefName.Equals(NS_LITERAL_STRING(kMaileditPrefKey))) {      rv = mCharsetMenu->RefreshMaileditMenu();    }  }  return rv;}