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

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2018 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>
        <shape
            android:shape="oval">
            <solid android:color="@android:color/white"  />
            <size android:width="48dp"
                android:height="48dp" />
        </shape>
    </item>
</layer-list>