A representation of a parsed CSS value. V is the type of the parsed
value, T is the StyleableProperty type of the converted value.
Instances of ParsedValue are created by the CSS parser. For example,
the parser creates a ParsedValue<String,Color> when it parses a
web Color.
A ParsedValue is meaningful to the code that calculates actual values from
parsed CSS values. Elsewhere the value returned by
getValue() is likely to be obscure, abstruse and perplexing.