helper_drag_root_scrollbar.html

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<!DOCTYPE HTML>

<html>

<head>

  <meta charset="utf-8">

  <meta name="viewport" content="width=device-width; initial-scale=1.0">

  <title>Dragging the mouse on the viewport's scrollbar</title>

  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>

  <script type="application/javascript" src="apz_test_utils.js"></script>

  <script src="/tests/SimpleTest/paint_listener.js"></script>

  <style>

    .content {

      width: 1000px;

      height: 5000px;

  </style>

  <script type="text/javascript">

async function test() {

  let scrollPromise = new Promise(resolve => {

    window.addEventListener("scroll", resolve, {once: true});

});

  // Do the scroll in one increment so that when the scroll event fires

  // we're done all the scrolling we're going to do.

  var dragFinisher = await promiseVerticalScrollbarDrag(window, 20, 20);

  if (!dragFinisher) {

    ok(true, "No scrollbar, can't do this test");

    return;

  // the events above might be stuck in APZ input queue for a bit until the

  // layer is activated, so we wait here until the scroll event listener is

  // triggered.

  await scrollPromise;

  await dragFinisher();

  // Flush everything just to be safe

  await promiseOnlyApzControllerFlushed();

  // After dragging the scrollbar 20px on a 1000px-high viewport, we should

  // have scrolled approx 2% of the 5000px high content. There might have been

  // scroll arrows and such so let's just have a minimum bound of 50px to be safe.

  ok(window.scrollY > 50, "Scrollbar drag resulted in a vertical scroll position of " + window.scrollY);

  // Check that we did not get spurious horizontal scrolling, as we might if the

  // drag gesture is mishandled by content as a select-drag rather than a scrollbar

  // drag.

  is(window.scrollX, 0, "Scrollbar drag resulted in a horizontal scroll position of " + window.scrollX);

waitUntilApzStable()

.then(test)

.then(subtestDone, subtestFailed);

  </script>

</head>

<body>

  <div class="content">Some content to ensure the root scrollframe is scrollable</div>

</body>

</html>