File photo of a driver displaying Uber and Lyft ride sharing signs on his car windscreen in Santa Monica Thomson Reuters Google announced Thursday that it's adding new ride-hailing partners to Maps.

Uber was already integrated into Maps. Now, users will also be able to see price estimates for Lyft and (in New York City) Gett, all without leaving the Maps app.

Basically, Google just created the first-ever ride-hailing price comparison tool.

There's only one problem: Uber has been specifically blocking startups from creating the same service.

In June, a Harvard startup called Urbanhail raised Uber's hackles by creating a price comparison tool for ride-hailing. Billed as "Kayak, but for rides," Urbanhail was using Uber's API within its app — something Uber allows, but not if it violates the company's terms of use.

Uber asks those who use its API to be "a strong, trustworthy partner to Uber" and specifically states that those who use the API cannot compete with or try to drive traffic away from Uber, or aggregate Uber with its competitors.

When Urbanhail launched, Uber's head of developer experience, Chris Messina, reportedly contacted Urbanhail and offered a trade: follow Uber's terms of use and Uber would either feature Urbanhail, give revenue in exchange for referrals, or grant access to the developers' "Insiders Program." Otherwise, Urbanhail's access would be revoked.

When Urbanhail didn't comply, Uber blocked the startup's access to its API.

Google gets a free pass

Uber's partnership with Google is technically different: it's a direct integration and doesn't use Uber's API, so it's not a violation of the terms of use.

Google has partnered with other ride-hailing services through Maps before — Ola in India and 99Taxis in Brazil, among others — this is the first time it's adding direct competitors to Uber in the US.

So why Uber was willing to work with Google to build a price comparison tool, while simultaneously blocking startups like Urbanhail?

The most likely reason is because Uber needs Google. Google Maps has hundreds of millions of users, so this means more exposure and more riders for Uber — the price comparison aspect is just an unfortunate side effect that Uber has to accept, or risk losing that exposure.

We asked Uber if the Google deal could be a catalyst for opening up Uber's API to startups, but it had no comment.

Lyft also declined to comment on the price-comparison aspect of the new partnership, but seemed happy to get the new exposure through Google Maps.

"We're always working to make sure Lyft is where our passengers — whether that's in the cities they live or integrated into the apps they use everyday," Lyft said in a statement. "Working with Google Maps makes it even easier to seamlessly request a ride with Lyft. From our work with Google Maps to Maps in iOS 10, there's a clear trend more and more people are clamoring for rideshare transportation options."