WordPress/src/main/res/drawable/scrollbar_transparent_black.xml

<?xml version="1.0" encoding="utf-8"?>

<shape
    xmlns:android="http://schemas.android.com/apk/res/android">

    <solid
        android:color="@color/translucent_grey" />

    <size
        android:width="3dp" />

    <stroke
        android:width="0dp" />

</shape>