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

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2015 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. -->

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item>
        <bitmap
            android:src="@drawable/infobar_shadow_top"
            android:gravity="top|fill_horizontal"
            android:tileMode="disabled" />
    </item>
    <item
        android:top="@dimen/infobar_shadow_height"
        android:drawable="@color/infobar_background_color" />
</layer-list>