It's a feature that Google put into the Chrome browser starting at around version 32 I believe. What it does is adds an icon to the Developer Tools console to toggle the device on or off and renders the page in the Chrome browser using the screen resolution of the emulated device. This device can be configured in the addtional settings for the Developer Tools in Chrome.
You can turn the emulation on and off to see the page render.
There is nothing special you need to do with UFT. Start it normally with the Web addin, launch Google Chrome, turn on the device emulation, and record on the smaller emulated page just like you would any other website.
As you can see, it doesn't replace something like Mobile Center or Perfecto and is only able to test a mobile version of the Chrome browser.
I've put together a little tutorial document that will walk you through the steps to get it setup that you might find useful and will attach it.[link text][1]
[1]: /storage/temp/431-mobile-device-emulation.pdf