GR:AW PC could be on your PC sometime next week according to this post by a moderator in the French Ubisoft forums. The best translation I can come up with at this time is…

“Well, the demo is out next week!  One of the folks that were at the fan’s day yesterday asked the question and one said for them that the demo is due out next week but no exact date was specified.” 

Keep your eyes peeled on the official sites for the exact date and content of the demo. Forum discussion here.