It’s pretty simple, just install the chrome extension, click the icon and then hover over text in the page. It will let you know what font family is being used. If you click on text it will give you all of the info you are looking for: font-family, font-size, line-height, color, and how it is served, Google Fonts, Typekit, etc.
More Info & Download
You can get more info and download the extension here