chromium/third_party/blink/web_tests/svg/animations/resources/change-baseVal-while-animating-fill-remove.svg

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1 Tiny//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-tiny.dtd">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">

<!-- an1: Change width from 10 to 50 in 4s, a script at 2s will set the width attribute to 100, fill is not freeze, so after the animation ends it should set width to 100 -->
<rect width="10" height="100" fill="green">
    <animate id="an1" attributeType="XML" attributeName="width" fill="remove" from="10" to="50" begin="0s" dur="4s"/>
</rect>

</svg>