Back in February, some commits to the Chromium codebase revealed that Chrome OS would soon run Linux applications using a container. While it has been possible for years to run Linux applications on top of Chrome OS using crouton, it's a hacky solution that only works in Developer Mode. Google's solution would presumably work better, and perhaps not require Dev Mode to be enabled.
More evidence of this feature has appeared in the Chrome OS Dev channel, as reported by several Reddit users. A new Terminal app has been added to the app drawer, and clicking it opens a dialog explaining the feature. The message is identical to the concept posted to the Chromium Gerrit in February.
Unfortunately, clicking 'Install' brings up an error, so the app is not actually functional yet. Still, it's exciting to see Linux app support come together, even if we'll probably have to wait until Google I/O for the official announcement.