Yeah, it's actually way simpler than that since chrome (and I think Firefox now too) is exposing a API for driving the browser, what you're after is the remote debugging protocol: https://chromedevtools.github.io/devtools-protocol/
But, you have bunch of things that abstract that for you, so you don't have to implement things hitting that API manually. Anyways, here is a handy document from Mozilla on the protocol too: http://searchfox.org/mozilla-central/source/devtools/docs/ba...