The dates on the site say this was posted before Apple's announcement, though dates can obviously be munged.
On-screen keyboards and context menus have significant prior art.
Re:Google Shows Off its Tablet Concept
by Confusion on Tuesday February 02, 2010 @01:25AM
(#1094455)
The keyboard and popover menus in those pictures look like direct rips of Apple's tablet
It is a pretty obvious choice to do it that way. Saying it's a rip off of Apple's tablet is like saying every car 'rips off' a carriage. The same thing will usually be invented multiple times you know.
An Apple designer wouldn't even show their manager concept drawings this rudimentary, especially if they were nothing more than copies of a competing product released the week before.
I really hope this isn't Google's doing. But if they are working on a tablet version of Chrome OS, they should probably keep the lid on it until it's had more than 2 hours of mockup work.