It appears that the ChromeOS team is experimenting with touch enabled features in ChromeOS with Francois Beaufort posting a video on Google+ of the new feature. The on-screen keyboard was reported a while back but now appears to be available, at least to those running in the Dev Channel.
The on-screen keyboard is made available by enabling a flag in Chrome via chrome://flags and obviously a device with Touchscreen is required to utilise the feature, meaning that at this stage the only device using it is the Chromebook Pixel.
Once you enable the flag, you’ll need to restart your Chromebook and then the keyboard basically appears on-screen whenever a text field is selected.
With the Pixel being the only device that can currently use the on-screen keyboard, it’s a fairly niche option. Rumours are circulating of lower end touch-screen based ChromeOS devices coming out around Google IO and with Windows 8 touch-screen laptops heading into the lower end of the market this is not a great stretch. Check out the video of the on-screen keyboard in action below :