As of January, 2017, Google already purchased a piece of Twitter, called Fabric. Fabric is used by developers to create mobile-app tools for Apple’s iOS software for iPhones and Google hopes to make it easier for developers to create similar apps for their Android software. Crashlytics, a popular Twitter tool for tracking software failures was also part of the 2017 purchase.
As of January, 2018, I don’t believe Google has any intention of buying the rest of Twitter. Other companies like Apple, Disney, and Salesforce once considered buying Twitter, back in 2016, but no sales happened. It’s not entirely clear why.