Number Tabs in Chrome or Firefox

I like to use the Ctrl or Alt + Number shorcut to jump quickly to a specific tab. Problem is: When you have a lot of tabs open it is hard to look at them and quickly know which one is tab number 7.

Is there a way (extension possibly) to show a tab's number in its title?
This way each tab would have a number added to its title right beside the favicon. This way you could immediately tell which number you need to press to jump to a specific tab.

I use both Chromium and Firefox, so I'm accepting answers for either one (though I'd prefer both =) ).

All of the linked extensions are gone now, probably because of the Firefox Quantum update.

Fortunately, there is a new extension called "Tab Numbering" that does the same thing:

https://addons.mozilla.org/en-US/firefox/addon/tab-numbering/

Mouseless Browsing does this for Firefox (and does a lot more too). I haven't found something as comprehensive for Chrome.

I found NumExt for Firefox that numbers the tabs for you.

NumExt numbers your tabs with no limitation on how many tabs you can open. The numbering is done using simple text, adding no overload on the tabs. It is therefore a very lightweight, straight forward useful extension for those who wish to number their tabs. NumExt colors your tab as well and does more...