There have always been closed source Google apps. Originally, the group consisted mostly of clients for Google’s online services, like Gmail, Maps, Talk, and YouTube. When Android had no market share, Google was comfortable keeping just these apps and building the rest of Android as an open source project. Since Android has become a mobile powerhouse though, Google has decided it needs more control over the public source code.
Google’s real power in mobile comes from control of the Google apps—mainly Gmail, Maps, Google Now, Hangouts, YouTube, and the Play Store. These are Android’s killer apps, and the big (and small) manufacturers want these apps on their phones. Since these apps are not open source, they need to be licensed from Google. It is at this point that you start picturing a scene out of The Godfather, because these apps aren’t going to come without some requirements attached. While it might not be an official requirement, being granted a Google apps license will go a whole lot easier if you join the Open Handset Alliance. The OHA is a group of companies committed to Android—Google’s Android—and members are contractually prohibited from building non-Google approved devices. That’s right, joining the OHA requires a company to sign its life away and promise to not build a device that runs a competing Android fork.