chromium/android_webview/java/res/drawable/aw_context_menu_bg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright 2024 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">
     <solid android:color="@color/dialog_bg_color_baseline" />
</shape>