XftTextExtents16(GDK_DISPLAY(), mXftFont, (FcChar16 *)aString, aLength, &glyphInfo);
nsFontXft::GetWidth16(const PRUnichar *aString, PRUint32 aLength){    XGlyphInfo glyphInfo;    if (!mXftFont)        GetXftFont();    // casting away const here on aString - should be safe    XftTextExtents16(GDK_DISPLAY(), mXftFont, (FcChar16 *)aString,                     aLength, &glyphInfo);    return glyphInfo.xOff;}