The Chromebook Pixel had all the hallmarks of a fake, a very well designed fake, but a fake nonetheless. However, while the video, the name and even the device may be fake, there are some elements that don't appear to be.
They pulsate blue when the battery is OK, turn to red when the battery is low and cycle the Google colors when waking up the device.
Granted, the documentation is five months old, but any device this important would have been in development longer than that.
In fact, given that the info has been public for so long would explain why it made it into the fake Chromebook Pixel ad.
The codename for this upcoming Chromebook is Link and we know for sure it's coming. While there are many unknowns, it seems to be a flagship device for Google, possibly sporting a Retina-class display and touch input.
It's also possible that it's going to be powered by a Tegra 4 SoC, though that may turn out to be another Chromebook altogether. We'll find out in a few months at Google I/O.