TJ Luoma wrote a blog post on Engadget describing how to use a combination of Fluid and Choosy to create a segregated browsing environment for browsing Facebook. This extension presupposes you've configured your computer according to TJ's excellent advice.
Fluidbook is a simple extension for Safari and Chrome that monitors for Facebook requests and redirects them to Choosy for opening in your dedicated Facebook Fluid app.
This extension uses the x-choosy:// URL scheme to open the URL in Choosy. The first time this occurs in Chrome,
you might see a prompt asking how you'd like to handle that situation. To make sure things go smoothly, you can
choose to open a Choosy URL outside of this extension first and tell Chrome to always handle them the same way.
Here's a nice URL you can use: x-choosy://open/https://agilebits.com/onepassword (You'll have to copy and paste
because Github won't auto-link the x-choosy URL scheme.