chromium/chrome/browser/ui/android/omnibox/java/res/drawable/status_view_highlight_background.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2023 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">
  <!-- Background for the hovered and pressed state -->
  <item
      android:width="@dimen/status_view_highlight_size"
      android:height="@dimen/status_view_highlight_size"
      android:gravity="center">

    <shape android:shape="oval">
      <solid android:color="@color/toolbar_button_highlight_color" />
    </shape>
  </item>
</layer-list>