NS_IMETHODIMP nsPref::AddObserver(const char *aDomain, nsIObserver *aObserver)
NS_IMETHODIMP nsPref::AddObserver(const char *domain, nsIObserver *observer)
NS_IMETHODIMP nsPref::AddObserver(const char *aDomain, nsIObserver *aObserver){  nsresult rv;  nsCOMPtr<nsIPrefBranchInternal> prefBranch = do_QueryInterface(mPrefService, &rv);  if (NS_SUCCEEDED(rv))    rv = prefBranch->AddObserver(aDomain, aObserver);  return rv;}