I don't understand why Chrome don't implement something similar to LocationBar2[1]. It expands to include the protocol when URL bar is focused, and hides the protocol on unfocus. It also tries to make sure text width never changes when protocol is hidden by center-aligned the domain part, e.g.
URL: http://news.ycombinator.com/item?id=1829087
When protocol is hidden, will be displayed as: URL: news.ycombinator.com /item?id=1829087
[1]: https://addons.mozilla.org/en-US/firefox/addon/4014/