NS_IMETHODIMP nsWidget::GetPreferredSize(PRInt32& aWidth, PRInt32& aHeight) { return NS_OK; }
inline NS_IMETHOD GetPreferredSize(PRInt32& aWidth, PRInt32& aHeight) { aWidth  = mPreferredWidth; aHeight = mPreferredHeight; return (mPreferredWidth != 0 && mPreferredHeight != 0)?NS_OK:NS_ERROR_FAILURE; }
NS_IMETHODIMP nsWidget::GetPreferredSize(PRInt32& aWidth, PRInt32& aHeight){  return NS_OK;}