chromium/third_party/blink/manual_tests/autoscroll-when-outside-window.html

<html>
    <body>
        <p>Click somewhere in this text, then quickly drag past the bottom of the window and hold still to allow auto-scrolling to happen.</p>
        <div style="height:3000px"></div>
        <p>If the bug occurs, then this text won't be selected until you move the mouse slightly. If the bug does not occur, this text should be selected.</p>
    </body>
</html>