I have tried to create a Gmail web application through Chromium; it works but, opens up in a new window without navigation, toolbar, etc. I remember that in older versions of Ubuntu Unity, when navigating to gmail.com on Chromium the webapp icon would appear on the app tray. This was important so that Gmail (and other webapps) could have access to the HUD feature.
14.04 LTS is such a solid release but Webapps should be fixed! This is disappointing as it's an important feature left out of an LTS release.