/**
  * Set or clear the xfermode object.
  *
  * <p>Pass null to clear any previous xfermode. As a convenience, the parameter passed is also
  * returned.
  *
  * @param xfermode May be null. The xfermode to be installed in the paint
  * @return xfermode
  */
 public Xfermode setXfermode(Xfermode xfermode) {
   int xfermodeNative = 0;
   if (xfermode != null) xfermodeNative = xfermode.native_instance;
   native_setXfermode(mNativePaint, xfermodeNative);
   mXfermode = xfermode;
   return xfermode;
 }