Chrome OS is that Dex always wanted to be. The real value would be giving a Chrome OS like experience when the phone is connected to an external display instead of the current Dex experience.
Samsung is could be working on a mashup between a Chromebook and a Dex dock for its line of Galaxy smartphones. The details on the device are scant at this stage, although it suggests Samsung is keen to more deeply integrate its hardware in the vein of Apple.