I have two buttons at each bottom corners of the MapView, partly obscuring the google logo in the bottom-left corner.
In order to comply with the terms
From the documentation :
protected final void onDraw(android.graphics.Canvas canvas)
onDraw is final method. This can't be overridden at all.
You can alternatively, show your buttons below mapview in layout aligned to parent bottom. This way you can have buttons at the position where you like and it will not obscure your google logo.