Google Maps actually rolled out the feature for Uber way back in 2014 and other competing ridesharing services were added outside the US earlier this year, alongside Gett in New York City. With today's addition of Lyft, Google Maps now offers options from nine different ridesharing services in 60 different countries. (Of course, which options are available to you will depend on which city and country you're in.)
The ride hailing feature works exactly as you might expect: a "ride services" tab with a taxi icon now shows up alongside the driving, transit and walking directions. Switching to the tab brings up a list of available ridesharing services and the various ride types, such as Lyft Line or UberX, offered by each. Lyft estimates should start showing up for users wherever Lyft is available, but Gett is still limited to New York City for now.