visual-viewport/viewport-no-resize-event-on-overflow-recalc.html

<!doctype html>
<html>
    <head>
        <title>Viewport: No Resize Event Fired on Overflow Recalc</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, minimum-scale=1">
        <script src="/resources/testharness.js"></script>
        <script src="/resources/testharnessreport.js"></script>
        <style>
          html {
              height: 100%;
          }
          body {
              /* Ensure overflow to start */
              height: 200%;
          }
        </style>
    </head>
    <body>
    <h1>No Resize Event Fired on Overflow Recalc</h1>
    <h4>
        Test Description: This test ensures we don't fire spurrious resize
        events when overflow is recalculated.
    </h4>
    <script>
      function runTest() {
        var t = async_test(
            "Resize event not fired at window.visualViewport when content is added");
        var viewResized = false;
        window.visualViewport.addEventListener('resize', function() {
            viewResized = true;
        });

        requestAnimationFrame(t.step_func_done(function() {
            assert_equals(viewResized, false);
        }));

        document.body.style.height = "400%";
      }

      // Run the test after load to make sure any resize from load doesn't
      // interfere.
      window.onload = requestAnimationFrame(function() {
        requestAnimationFrame(runTest);
      });
    </script>
    <div id="log"></div>
    </body>
</html>