// http://www.w3.org/TR/css3-syntax/#consume-a-numeric-token
CSSParserToken CSSTokenizer::consumeNumericToken()
{
    CSSParserToken token = consumeNumber();
    if (nextCharsAreIdentifier())
        token.convertToDimensionWithUnit(consumeName());
    else if (consumeIfNext('%'))
        token.convertToPercentage();
    return token;
}
static CSSParserToken percentage(NumericValueType type, double value)
{
    CSSParserToken token = number(type, value, NoSign); // sign ignored
    token.convertToPercentage();
    return token;
}