chromium/chrome/android/java/res/drawable/capture_overlay_border.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2021 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
    <stroke android:width="5dp" android:color="@color/baseline_primary_40_alpha_65"/>
</shape>