I just updated Google Chrome
16.0.912.77 m and when I watch YouTube videos, and make them full screen, Chrome wants to confirm with me that its OK to have YouTube.com in full screen.
How do I prevent Chrome from asking me this for any site?
There is no way to prevent this - this message is by design to stop malicious webpages.
If this was not the case, a malicious website could become fullscreen and show you a picture of Google Chrome with the URL bar and HTTPs logo showing you that you're securely talking to bankofamerica.com, but with the webpage secretly sending your login credentials to joes-malware-site.com.