I'm writing extenstion for chrome and I need to check performance of it. But making multiple requests to other sites I think can put you on a black list as a suspect of doing DoS attack. So I need a local proxy that would fetch given website once and then would fetch only from local storage and would not even try to compare what's in local with what's online.
Is Squid an option? There is a windows version if I recall. Actually, check out this other Super user post.
Why don't you just create a website locally anyway and use Chrome to connect to this instead?
I say this because that is what you are effectively doing anyway if you use a proxy to cache a website. It is no longer going out on the internet so you can't test the performance of the line this way (if needed). Instead the web page is served from the cache (which is local). So why not just create a local website to achieve this?