While it hasn’t always been clear just how big of a bet Google was going to make on Chrome OS, after Google I/O today, it seems very clear that they’re very serious. With the launch of Chromebooks, Google is aiming to strike right at the heart of Microsoft and the Windows stronghold. But they know that one big hold up remains before a browser-based OS can be everywhere: offline access.

With that in mind, on stage today, Google’s Sundar Pichai revealed that Google has internally been using offline versions of their three most popular apps for months now: Gmail, Google Calendar, and Google Docs. And this summer, all users will be able to use these apps offline too.

All of this is a long time coming for Google. They’ve had options for going offline in the past with things like Gears, but it wasn’t perfect. And actually, Gears is no longer being supported by Google as Chrome gains many of the same features via HTML5.

Pichai also noted that there are already hundreds of apps in the Chrome Web Store with offline access. And that includes almost every game in the store. This, on top of the built-in 3G connectivity is all vital to ensure the vitality of Chromebooks, Pichai noted.