This is a chrome extension.
Functionality:
The extension closes all tabs except the active tab in the current window, and stores their URLs in the default popup of the browser action, when the icon for the same is clicked.
Then, while in the same window[not only tab, any tab you open in the same window], you can click the browser action icon again, to find the list of URLs and clicking any of them will open the specific URL in a new tab in the same window.
This list is available in all tabs till one quits the window.