Using app:layout_anchor and app:layout_anchorGravity in Floating Action Buttons guide is problematic

This is the page I'm talking about:
[Floating Action Buttons](https://guides.codepath.com/android/Floating-Action-Buttons)

I've described the problem here:
[Android Issue 227432: Rotating screen after pressing FAB causes Espresso to fail on API 19 devices](https://code.google.com/p/android/issues/detail?id=227432)