Word of the "Chrome EC" embedded controller came via a Coreboot commit that came on Friday afternoon for supporting the new chip. Stefan Reinauer, one of the original Coreboot developers that is now employed by Google, wrote "Add support for Google ChromeEC - Google ChromeEC is an EC with completely open source firmware...This patch adds support for the ChromeEC on coreboot's side. Great thanks to the ChromeEC team for this amazing work. It's another important milestone towards a free and open firmware stack on modern hardware."
Cited from that commit is a Chromium Git repository that contains the source-code to the firmware for this Google Chrome EC. The embedded controller is responsible for different background tasks of the system like battery information, keyboard initialization, temperature sensors, controlling USB charging, and other tasks.
It's rather interesting that Google's Chrome team has taken to designing their own EC and now for this GoogleEC being supported by Coreboot along with Compal, Lenovo, Quanta, and SMSC. With the mainlining of ChromeEC support, presumably this embedded controller will end up appearing in a released Chromebook? Which one? Well, seeing as this announcement comes just one day after Google announced the Chromebook Pixel and they already started pushing Pixel Linux support, it wouldn't be a big surprise if this Google EC ends up in their first high-end notebook.
Google keeping the Chrome EC open down to the firmware is also much appreciated by open-source fans and seeing that the embedded controller becomes widely-supported by the free software operating systems. With their heavy backing of Coreboot, now an open-source EC, and various other initiatives, it will be interesting to see what other areas of low-level open-source hardware support they apply their pressure to next for Chrome products.