While using pdfjs in frameworks with SSR like Next.js or Gatsby there is an error while build phase
```ReferenceError: window is not defined```

The error occurs at line 563 in `ui_utils.js`

Looks like all changes needs is:
```diff
const animationStarted = new Promise(function (resolve) {
  if (
    typeof PDFJSDev !== "undefined" &&
-   PDFJSDev.test("LIB && TESTING") &&
+   PDFJSDev.test("LIB && TESTING") ||
    typeof window === "undefined"
  ) {
    // Prevent "ReferenceError: window is not defined" errors when running the
    // unit-tests in Node.js/Travis.
    setTimeout(resolve, 20);
    return;
  }
  window.requestAnimationFrame(resolve);
});
```

There is an issue in react-pdf: https://github.com/wojtekmaj/react-pdf/issues/657
elt = views[index - 1].div;
    pageTop = elt.offsetTop + elt.clientTop;
  }
  
  
  
  
  
  
  
  
  for (let i = index - 2; i >= 0; --i) {
    elt = views[i].div;
    if (elt.offsetTop + elt.clientTop + elt.clientHeight <= pageTop) {
      
      
      
      break;
    }
    index = i;
  }
  return index;
}
/**
 * @typedef {Object} GetVisibleElementsParameters
 * @property {HTMLElement} scrollEl - A container that can possibly scroll.
 * @property {Array} views - Objects with a `div` property that contains an
 *   HTMLElement, which should all be descendants of `scrollEl` satisfying the