I have worked with several themes that provide Google Font

I have worked with several themes that provide Google Font support, whereby that actual font shows up in the drop down list of available fonts. Meaning, when you see the word 'Arial' it is in Arial font -- Century Gothic is in Century Gothic font. It is a dynamic font preview in the font list.

Is there a plugin that anyone knows of that I can use in other themes that will allow me to see this font preview? As it is now, many themes have a listing of fonts available, but I have no idea of what they look like.

Thanks,
Jeff