How to replicate the FAB animation used by the Google Authenticator

How is this animation done?

I tried this so far but I don't like it that much, it looks like it's scaling the Y from the bottom

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/accelerate_interpolator">
    <scale
        android:duration="100"
        android:fromXScale="1"
        android:fromYScale="0"
        android:pivotX="50%"
        android:pivotY="100%"
        android:toXScale="1.0"
        android:toYScale="1.0" />
</set>