Chrome extension search : specific website timer

I'm searching a google chrome extension to reduce my time wasted on some website (facebook, youtube etc...)

Here is the behavior I'm searching for:

• I want to be able to add any procrastination website url (facebook, youtube...)in the extension preference panel.
• Then, every 5 minute I spend on this particular website, I want a notification to appear to inform me how much time I have wasted. ( for example a javascript popup saying "you have wasted 20 minute on this website today"). Then, 5 minute later, the popup appear again, saying "you have wasted 25 minute on this website today"

So far, I have found 2 extension that should do this job but don't work:

https://chrome.google.com/webstore/detail/timestats/ejifodhjoeeenihgfpjijjmpomaphmah?hl=en

The timer of this extension work well, I have set up the alert to show up every 5 minute, but the alert never shows up. Probably a bug.

• Time's Up!

https://chrome.google.com/webstore/detail/times-up-facebook-time-li/odjlcinlanjcnogakmjmjhmblfddmmlj?hl=en

This one only works with facebook (and not youtube etc...) and the alert appear every 5 minute, even if facebook isn't the active tab...

I have literally spent hour searching for a working extension like the one I have described. Maybe someone can help me ? Maybe a developer around here find this idea interesting and can develop it ?