LayoutTests/fast/dom/MutationObserver/transient-gc-crash.html

<script src="../../../resources/js-test-pre.js"></script>
<script>
window.jsTestIsAsync = true;
description('Clearing transient observers after observation node is GCed should not cause a crash.');

function callback(mutations) {
    window.mutations = mutations;
}
var observer = new MutationObserver(callback);

var div = document.createElement('div');
var span = div.appendChild(document.createElement('span'));
observer.observe(div, {attributes: true, subtree: true});
div.removeChild(span);
div = null;
gc();
span.setAttribute('foo', 'bar');
setTimeout(function() {
    shouldBe('mutations.length', '1');
    finishJSTest();
}, 0);
</script>
<script src="../../../resources/js-test-post.js"></script>