Unfortunately, nope, you can't get the "real" fs (and any other node stuff) inside a normal chrome browser.
The magic of node-webkit is in the combination of node.js, and chromium browser (former webkit, currently blink), hence the node-webkit. check the git project hosted on github for more info on nodewebkit.
You could check out the awesome browserify-fs project (https://github.com/mafintosh/browserify-fs) it has the "fs" module implementation for chrome, but it does not give you access to the whole system, it just emulates "fs" inside leveldb so you cannot read some file on c:/documents/whatever , it just stores a file inside local storage. (but you can store a pdf using browserify-fs, or a .doc, or a .capx file, if you're into it)
I didnt use the browserify-fs project yet, so you're on your own there, but it might be useful, depending on your requirements.
edit: looks like browserify doesent support fs check out: www.browserify.org