<!doctype html>
<html>
    <head>
        <title>Viewport: Resize Event On Load Overflowing Page</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>
        <script src="viewport_support.js"></script>
        <script>
            // This first case ensures that we load into the same kind of
            // viewport. If the previous test had a page-scale factor set or a
            // different viewport <meta> we might get a resize because of that.
            if (location.search === "") {
                window.addEventListener('load', function() {
                    var url = window.location.href + "?reloaded";
                    window.location.href = url;
                });
            } else {
                var t = async_test(
                    "Resize event fired exactly once against window.visualViewport if " +
                    "scrollbars affect layout.");
                var numViewResizes = 0;
                window.visualViewport.addEventListener('resize', function() {
                    numViewResizes++;
                });

                window.addEventListener('load', function() {
                    var count = 0;
                    requestAnimationFrame(function step() {
                        // Wait for two RenderingUpdates before checking the value of numViewResizes.
                        if (count++ < 2) {
                            requestAnimationFrame(step);
                            return;
                        }

                        requestAnimationFrame(t.step_func_done(function() {
                            var isOverlay = calculateScrollbarThickness() == 0;
                            assert_equals(numViewResizes, isOverlay ? 0 : 1);
                        }));
                    });
                });
            }
        </script>
        <style>
          html {
            height: 100%;
          }
          body {
              /* Ensure overflow */
              height: 200%;
          }
          #log {
              overflow: auto;
          }
        </style>
    </head>
    <body>
    <h1>Viewport: Resize Event On Load Overflowing Page</h1>
    <h4>
        Test Description: This test ensures that we fire a resize event against
        window.visualViewport if the page has overflow (since this creates a scrollbar
        and thus changes the viewport size).
    </h4>
    <div id="log"></div>
    </body>
</html>