WindowScript.js

// Security: Code here is exposed to the website.
// Automaticly add media elements to DOM.
(function () {
  'use strict';

  // This is okay because the HTMLMediaElement prototype gets hooked.
  // Note to self: DO NOT CHANGE NAME
  if (window.autoPauseExtensionInjected) return;
  window.autoPauseExtensionInjected = true;

  const play = window.HTMLMediaElement.prototype.play;
  let div = null;
  window.HTMLMediaElement.prototype.play = function () {
    try {
      if (this instanceof HTMLMediaElement && !this.isConnected) {
        if (!document.contains(div)) {
          div = document.createElement('div');
          div.hidden = true;
          document.head.appendChild(div);
          // If media gets paused remove it from the div
          div.addEventListener(
            'pause',
            (event) => {
              const src = event.srcElement;
              if (src instanceof HTMLMediaElement) {
                div.removeChild(src);
              }
            },
            {passive: true, capture: true}
          );
        }
        div.appendChild(this);
      }
    } catch {
      // Extension errors should not affect the API.
    }
    return play.apply(this, arguments);
  };
})();