See  issue 147 

As per comment #3, as this is marked as Feature request, changing the status to 'Untriaged' for further updates from Dev.

Thanks..

We've discussed this UI in the past.  Because Chrome provides the ability to undo tab closure, confirmation prompts before closing are less critical.  Additionally, prompts train people to click through them as part of the process of closing tabs, meaning that they often don't save you when you realize you wanted to keep a tab open (because of reflexively clicking "yes").  Finally, we wouldn't prompt by default, and Chrome's design philosophy of not adding options unless absolutely necessary precludes adding this as an option.

The one behavior I wouldn't necessarily mind seeing is some sort of transient "press ctrl-shift-t to reopen this tab" reminder the first few times you close a tab, to teach people about that feature/shortcut.

I think another area that could be improved here is restoring works on a per tab basis. So, even though it's possible to close multiple tabs at once they are not restored as a group. I suspect there is a bug on this.

Yeah, hitting ctrl-shift-t after a single mass-close event should mass-restore.  I suspect you're right that there's a bug on this somewhere.