chromium/chrome/android/features/tab_ui/java/res/drawable/tab_strip_fading_edge_start.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2020 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" >
<gradient
    android:startColor="@macro/default_bg_color"
    android:endColor="@color/white_alpha_8"
    android:type="linear" />
</shape>