The Android Device Manager has been a useful security feature for a while, but hunting down the right bookmark when you can't find your phone is a mild hassle. Now, instead, you can simply type "find my phone" into Google from any desktop you're logged in on.
The new feature is an extension of the same features found on the Android Device Manager dashboard. You can select which device you're looking for from a drop-down menu, see its location on a map, and even ring it. A Google search box is arguably the quickest way to pull up this info, so it's a nice addition.