Yes, but using built-in hardware to do it. Mark my words, there will be an ad library built that developers can include into their program that will force you to watch the ad. Software developers can choose not to use it, but they most likely will because of the insanely high conversion rate compared to other forms of advertising (which you can choose to ignore).

It doesn't even have to be this way. It seems to me like a better way of doing VR in general is not to have a screen that the computer itself renders to, but to have the VR headset accept 3D scenes from the computer (perhaps using an OpenGL/DirectX injector to get the data from the scene and passing it along to the headset), which the headset can then render and display. This has several advantages:

1. The headset can guarantee that it will keep displaying and tracking at 75Hz/90Hz, even when the computer is having trouble keeping up. New objects might pop into existence when this happens (say, if you turn your head) rather than coming in naturally, but nothing's perfect and as an alternative it's far better than feeling sick because the scene isn't changing.
2. The eye tracking can't be used for nefarious purposes because the only thing that needs it is the hardware - and let's face it, this is the sort of thing that should be standard anyway. I literally cannot see any use for eye tracking outside of the scene-rendering layer that isn't creepy and/or a bad idea. The only reason you should want to know what someone is looking at is to allow you to render that part of the image in more detail.
3. Less data has to be transmitted over the link, which is important if you want to become wireless (and you should; wires are incredibly easy to tangle, especially with VR). You don't need to transmit the entire display every time, you just update the 3D scene and transmit the changes.

Obviously, the major downside - and probably the reason why VR is just now becoming popular in the first place - is because putting this stuff on the headset itself will raise the price of the headset. Doing everything in software is cheaper, and it does put more power in the hands of the game developers. The question is, how much power should they really have over something as intimate as what you see?