nsCOMPtr<nsIStreamLoaderObserver> loaderObserver  = do_QueryInterface(inSupports); nsCOMPtr<nsITimerCallback>        timerCallback   = do_QueryInterface(inSupports); if (!loaderObserver || !timerCallback) return nsnull;
nsCOMPtr<nsITimerCallback>  timerCallback = do_QueryInterface(inSupports); if (!timerCallback) return nsnull;
nsSoundRequest::GetFromISupports(nsISupports* inSupports){  if (!inSupports) return nsnull;    // test to see if this is really a nsSoundRequest by trying a QI to both  // interfaces we support  nsCOMPtr<nsIStreamLoaderObserver> loaderObserver  = do_QueryInterface(inSupports);  nsCOMPtr<nsITimerCallback>        timerCallback   = do_QueryInterface(inSupports);  if (!loaderObserver || !timerCallback) return nsnull;    return NS_REINTERPRET_CAST(nsSoundRequest*, inSupports);}