Google's Happiness Evangelist François Beaufort shared a video about how the Chrome OS team measures latency on Android and Chrome OS devices.
The team uses a robot created by Finnish company OptoFidelity, a company that specialises in automated testing. You'll see in the video how the little robot looks as though it's poking and prodding at various smartphones.
Called the Touchbot, its code is open source and available for everyone to look at.
Don't have your own little latency robot tester? Well you can still visit a website on Appspot to play with the tests.