You don't exactly have to tell them that you are carrying a handgun, but you do have to display the license. It's somewhat meaningless now, though, because the legislature removed the penalty for failing to display the license.
I've been pulled over a couple of times with my CHL. I handed the officer my CHL along with my driver's license. Once the LEO asked where my gun was, and told me not to reach anywhere near it, the other time the officer handed me back the license with no comment.
"Sec. 411.205. REQUIREMENT TO DISPLAY LICENSE. If a license holder is carrying a handgun on or about the license holder's person when a magistrate or a peace officer demands that the license holder display identification, the license holder shall display both the license holder's driver's license or identification certificate issued by the department and the license holder's handgun license."