I wouldn't use FB on a RPI (I have the new 3 B+ version). I actually stopped using it after I had my RPI. I tried, but it's one of those web sites (and the Internet is littered with them) that cripple a small system like the RPI. It just shows how hard they try to track and run various Java like programs under the bonnet. Actually FB on one my less powerfull PC's can just cause performance issue. Chromium is a hog in itself anyway.
If this helps......
“It’s nice to be important, but it’s more important to be nice.”