java/com/android/incallui/incall/impl/res/drawable/tab_indicator_selected.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
  <item>
    <shape
      android:innerRadius="0dp"
      android:shape="ring"
      android:thickness="4dp"
      android:useLevel="false">
      <solid android:color="@color/background_dialer_white"/>
    </shape>
  </item>
</layer-list>