<!DOCTYPE html>
<body>
    <div draggable="true" style="width: 200px; height: 200px" id="source">DRAG ME AND LET GO</div>
</body>
<script>
function forceGarbageCollection() {
    if (window.GCController)
        GCController.collect();
    else {
        for (let i = 0; i < 1000; i++)
            new ArrayBuffer(0x100000);
    }
}

source.addEventListener("dragend", event => {
    forceGarbageCollection();
    event.dataTransfer.items.clear();
    if (window.testRunner)
        testRunner.notifyDone();
});

source.addEventListener("dragstart", event => {
    event.dataTransfer.items.add(event.target.id, "text/plain");
    event.dataTransfer.items.add("Test1", "text/html");
    event.dataTransfer.items.add("Test2", "text/uri-list");
});

if (window.testRunner && window.eventSender && window.internals) {
    internals.settings.setCustomPasteboardDataEnabled(true);
    testRunner.waitUntilDone();
    testRunner.dumpAsText();
    eventSender.mouseMoveTo(100, 100);
    eventSender.mouseDown();
    eventSender.leapForward(1000);
    eventSender.mouseMoveTo(400, 400);
    eventSender.mouseUp();
}
</script>