chrome/android/java/res/drawable/ic_add.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2017 The Chromium Authors. All rights reserved.
     Use of this source code is governed by a BSD-style license that can be
     found in the LICENSE file. -->

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    tools:targetApi="21"
    android:width="24dp"
    android:height="24dp"
    android:viewportWidth="24.0"
    android:viewportHeight="24.0">

    <path
        android:pathData="M19,13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"
        android:fillColor="#000000" />
</vector>