Prevent Google Chrome for being Accidentally Force Close
Firstly, you need to pin a site (example I pin translate.google.co.uk). Then you need to install User Javascript and CSS extension.

Then, go to tab pinned tab! And click User Javascript and CSS extension you just installed, and add new.

Paste this code to javascript code (left side) :
window.onbeforeunload = function() {
return "You are closing all tabs.";
}

Then save it, and restart the pinned tab!
When you are trying to close whole browser, you will get this notice.
