Over on Google+ a senior Chrome developer has announced a test feature for Google Chrome which will do exactly that. When this feature is ready for general use by everyone, this will be HUGE.
Why? Browser-based applications are easier to develop and can run across platform fairly easy. It means Google is creating a whole new channel through which developers can sell/provide applications. Through this channel, a developer can reach users on any computing platform where Chrome runs, and their application will run as a first-class citizen on the platform. The platform mix includes Windows, Mac OS X, Linux, Chromebooks/Chromebox, and perhaps Android/iOS devices.
What the Chrome developer showed is that a Chrome app will now be able to associate with file types on Mac OS X. With the feature enabled, a Mac OS X user will be able to right click a file and see Chrome app's listed as an application with which to open the file.
The feature is only available in the developer-test build of Chrome (Canary), and to enable the feature you have to set a flag. Ergo, this is an experimental feature meant for developers and isn't (yet) ready for prime time.
While the feature is under limited distribution, and may seem like it's minor, this is a huge step. It's a significant step towards making Chrome applications a first class citizen, appearing in the application menu, appearing in the Finder, etc.