MCVE to demonstrate `requestAnimationFrame()` not being called in background browsers

Prerequisites

Podman
Maven >= 3.6

How to run the reproducer

Start

[sel-term] $ scripts/start-browser
[run-term] $ mvn clean package
[run-term] $ java -jar target/requestanimationframe-1.0.0.jar

Watch the browser using VNC

[new-term] $ echo "secret" | vncviewer -autopass 127.0.0.1:5900

Expected output

This is what you shall see when the reproducer is able to reproduce the error:

Info: start 3 test threads
Info: get driver
Info: get driver
Info: get driver
Info: connect to driver http://localhost:4444
Info: connect to driver http://localhost:4444
Info: connect to driver http://localhost:4444
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: wait for rendering-done selector
Info: wait for rendering-done selector
Info: wait for rendering-done selector
Info: selector found
Err :Timeout waiting for the selector By.cssSelector: #target.done to be visible
Err :Timeout waiting for the selector By.cssSelector: #target.done to be visible
Info: test successful

Logging related to Selenium and SLF4 was omitted for brevity. It usually starts with a timestamp, INFO: or SLF4J:. Relevant logs start with Info: and Err :.

If the error were not repoducible (were fixed)

This is what you shall see when the bug were fixed:

...
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: click on button will enqueue requestAnimationFrame() after 1s ...
Info: wait for rendering-done selector
Info: wait for rendering-done selector
Info: wait for rendering-done selector
Info: selector found
Info: selector found
Info: selector found
Info: test successful

tholewebgods/webdriver-requestanimationframe-mcve