<!DOCTYPE HTML>
<html>
<head>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <script src="/tests/SimpleTest/EventUtils.js"></script>
  <link rel="stylesheet" href="/tests/SimpleTest/test.css">
</head>
<body >
<input />
<script type="text/javascript">
  SimpleTest.waitForExplicitFinish();

  function runTest() {
    function checkResult() {
      ok(true, "didn't crash");
      SimpleTest.finish();
    }

    // Dispatch an vsync event to the queue
    window.requestAnimationFrame(() => {
      window.requestAnimationFrame(() => {
      });
    });

    // Dispatch the first input tasks. Since there's a vsync
    // task in the queue, so this task takes the priority and runs
    // first.
    SpecialPowers.Services.tm.dispatchToMainThread(function() {
      let secondInputRun = false;

      // Dispatch the second input task to the queue.
      SpecialPowers.Services.tm.dispatchToMainThread(function() {
        secondInputRun = true;
      }, SpecialPowers.Ci.nsIRunnablePriority.PRIORITY_INPUT_HIGH);

      // Inner event loop runs and picks the second input task to run.
      SpecialPowers.Services.tm.spinEventLoopUntil(
        "Test(vsync_alignment_inner_event_loop.html)", () => secondInputRun);

      setTimeout(checkResult, 0);
    }, SpecialPowers.Ci.nsIRunnablePriority.PRIORITY_INPUT_HIGH);
  }

  SpecialPowers.pushPrefEnv({
      set: [["dom.input_events.strict_input_vsync_alignment", true]]
  }, runTest());
</script>
</body>
</html>
