> implementing a program with the same API should be fine, right?
If this is all it comes down to, Google certainly should be fine with it being that they're in the middle of (end of?) a lawsuit with Oracle over their implementation of the Java API in Android.
Amazon has been providing drop-in replacement implementations of Google APIs (for proprietary Google services) for some time now. For instance:
"The Amazon Maps API offers interface parity with version 2 of the Google Maps API. Most classes and method calls in your Google Maps app work the same on Amazon devices. "
If this is all it comes down to, Google certainly should be fine with it being that they're in the middle of (end of?) a lawsuit with Oracle over their implementation of the Java API in Android.