This is my adapted code of the chrome cookie sample (https://developer.chrome.com/extensions/examples/api/cookies.zip). Chrome unlike Opera doesn't allow to edit cookies, which is a shame.
The famous chrome extension to edit cookies is said to use ads and as I don't like ads and at the moment don't have time to control other people's code, I just created my own editor. A simple diff with the original sample is sufficient to control my changes that are only marginal. So all praise goes to the sample programmer.
This extension is no product of Google and not otherwise connected to the Chromium project. Use at your own risk!