chromium/chrome/browser/download/internal/android/java/res/drawable/group_card_item_border.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2019 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:top="-2dp" android:bottom="-2dp">
        <shape
            android:shape="rectangle" >
            <solid android:color="@macro/default_bg_color" />
            <stroke android:width="1dp" android:color="@macro/hairline_stroke_color"/>
        </shape>
    </item>
</layer-list>