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Test Info:

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Largest Contentful Paint: observe image.</title>
<style>
#target {
background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="50"><rect fill="lime" width="100" height="50"/></svg>');
width: 100px;
height: 50px;
}
</style>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/largest-contentful-paint-helpers.js"></script>
<script>
async_test(function (t) {
assert_implements(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented");
const beforeLoad = performance.now();
const observer = new PerformanceObserver(
t.step_func_done(function(entryList) {
assert_equals(entryList.getEntries().length, 1);
const entry = entryList.getEntries()[0];
let url = 'data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg"';
url += ' width="100" height="50"><rect fill="lime" width="100"';
url += ' height="50"/></svg>';
// green.svg is 100 by 50
const size = 100 * 50;
checkImage(entry, url, 'target', size, beforeLoad);
})
);
observer.observe({type: 'largest-contentful-paint', buffered: true});
t.step_timeout(() => {
assert_unreached("The image should have triggered an LCP entry.");
t.done();
}, 1000);
}, 'Data-URI background SVG image is observable.');
</script>
<div id="target" width="100" height="50"></div>
</body>