session-android/res/drawable-v16/compat_actionbar_shadow_background.xml

<?xml version="1.0" encoding="UTF-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/conversation_item_sent_shadow_light" />
        </shape>
    </item>

    <item android:bottom="1dp">
        <shape xmlns:android="http://schemas.android.com/apk/res/android">
            <solid android:color="@color/conversation_list_divider_light" />
        </shape>
    </item>

</layer-list>