@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
    private boolean isDescendant(Fragment fragment) {
        Fragment root = this.getParentFragment();
        while (fragment.getParentFragment() != null) {
            if (fragment.getParentFragment() == root) {
                return true;
            }
            fragment = fragment.getParentFragment();
        }
        return false;
    }
Returns true if the fragment is a descendant of our parent.
core/src/main/java/com/bumptech/glide/manager/RequestManagerFragment.java