How do I know which Chrome font is using?

Question

Imagine I have the following CSS

font-family: 'Non-existant Sans', Arial, sans-serif; 

Assuming the system does not have “Non-existent Sans” installed, Arial will be used by the browser. Using Chrome, is there any way to know which font is being displayed?

Edit: Dave (in the comments on the question) pointed to a similar question. I specifically ask about Chrome here. Many answers in another question suggest extensions, which are fine; Is there any way to define this information using only Dev Tools?

Edit September 2013: The Chrome team just announced that font family validation is now available in the latest versions of Chrome Canary (Twitter link contains an image with additional information). That should leak through dev> beta> stable over the next few weeks - great news!

Answer 1

In Google Chrome, devtools on the Elements tab in the Calculate section:

Answer 2

I'm a bit late to the party, but I just discovered a very easy way to debug the font that your browser uses.

In Chrome Web Inspector, go to the font stack in the CSS panel of the Elements panel. Then, starting at the top of the stack, change the font name (I add random letters) while keeping an eye on the text. When you change what you are using, you will see a font for changing text when it returns to the next one on the stack.

I suppose something like this is possible in most dev tools

Voila

Answer 3

If you do not want to use the plugin, there is a bookmarklet that will tell you (after activation, and hover over the specified text):

http://chengyinliu.com/whatfont.html

Answer 4

Your "Non-existant Sans" can be rendered using @ font-face in your css. http://www.w3schools.com/cssref/css3_pr_font-face_rule.asp

I don’t know how to determine font rendering, so I don’t answer your question technically. I found this: http://webdesignerwall.com/tutorials/css3-font-face-design-guide is a javascript called Modernizr, which ensures that the browser does not support @ font-face, then it will load fallback fonts like Arial and Helvetica.