We wrote about this feature a few months ago and now we are seeing a first implementation of it. The URL bar in Chrome is still active by default, but there is a flag to hide it.
Chrome is serious about keeping the URL bar flexible: Some applications and users may not really need it and there is now an option to kill it. The effect is a 30 pixel gain in vertical space and transforms the standard viewing window in Chrome into a full-screen view. The downside: There is a security issue as users will not always notice the URL and are now much more exposed to phishing attacks, for example and not aware whether they are on a secure or unsecured website.
Instead of showing a URL bar permanently, the user will have to double-click a tab to see a shortened version of the URL that is displayed with a hover effect, if you move the mouse pointer away from the field, the URL bar disappears. The feature has to be enabled via a flag in a recent Canary or nightly build version of Chrome 13. To activate the hidden URL bar, users will also have to right-click a tab and select “Hide the toolbar”. Besides killing the URL bar, the new feature also moves the tools menu, hides any extension and introduces new back/forward buttons. To open a tab URL bar, click the tab once.
On a large desktop screen, killing the URL bar approach may be pointless, even if this is a clear move toward a full screen view to benefit web apps. It is mobile device that are the target and the true beneficiary of this technology, but then we know that there is no Chrome for Android (just a Chrome version for Chrome OS notebooks.) We still believe that Google will be offering a version of Chrome for Android in the not too distant future.
Google introduced the hidden URL bar feature in Chromium revision# 84971 as a “compact navigation” feature. There is no information when “cnav” will be moved into the final version, but it seems that this is a pretty final feature with a targeted Milestone 13 availability.