chromium/third_party/blink/web_tests/external/wpt/visual-viewport/viewport-scale-iframe-manual.html

<!doctype html>
<html>
    <head>
        <title>Viewport: Scale iframe</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>
           setup({explicit_done: true, explicit_timeout: true});
        </script>
        <style>
          iframe {
            width: 200px;
            height: 200px;
          }
        </style>
    </head>
    <body>
    <h1>Viewport: Scale iframe</h1>
    <h4>Test Description: Tests the visualViewport.scale property inside an iframe</h4>
    <h2 style="color: red">THIS IS A MANUAL TEST</h2>
    <p id="skip">
        <button id="skipbtn" onclick="skipManualTest();">Skip Test</button>
    </p>
    <p id="instruction"></p>
    <button id="continue">Start Test</button>
    <p>
        <iframe srcdoc="<!DOCTYPE html><style>html {background-color: coral;}</style>"></iframe>
    </p>
    <div id="log"></div>
    </body>
    <script>
        var continueBtn = document.getElementById("continue");

        function continueTest() {
          nextStep(function(instructionText) {
            var instruction = document.getElementById("instruction");
            continueBtn.innerText = "Continue";
            instruction.innerText = instructionText;
          });
        }

        continueBtn.addEventListener('click', continueTest);

        addManualTestStep(
            function() {},
            null,
            '1. Ensure the browser is at the default pinch and browser zoom ' +
            'levels (100%). Most browsers: ctrl+0');

        addManualTestStep(
            showPinchWidget.bind(null, 2.0, 0, 0, continueTest),
            null,
            '2.Follow instructions on pinch zoom dialog.');

        addManualTestStep(
            function() {
                // Ensure we zoomed in to about what we expect.
                assert_approx_equals(window.visualViewport.scale, 2.0, 0.2,
                    "Main window.visualViewport.scale reflects pinch-zoom level");

                assert_equals(frames[0].window.visualViewport.scale, 1.0,
                    "Iframe scale unchanged even when pinch-zoomed");
            },
            'Check iframe scale is unchanged when page is pinch-zoomed',
            '3. Pinch-zoom back out to the minimum scale');

        addManualTestStep(
            function() {
                continueBtn.remove();
            },
            null,
            'Test Complete');
    </script>
</html>