<!DOCTYPE html> <title>Access to the Web USB API is deferred</title> <meta name="timeout" content="long"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="/common/utils.js"></script> <script src="/speculation-rules/prerender/resources/utils.js"></script> <body> <script> setup(() => assertSpeculationRulesIsSupported()); promise_test(async t => { const uid = token(); const bc = new PrerenderChannel('test-channel', uid); const gotMessage = new Promise(resolve => { bc.addEventListener('message', e => { resolve(e.data); }, { once: true }); }); const url = `resources/web-usb.https.html?uid=${uid}`; window.open(url, '_blank', 'noopener'); const result = await gotMessage; const expected = [ {event: 'started waiting navigator.usb.getDevices', prerendering: true}, {event: 'prerendering change', prerendering: false}, {event: 'finished waiting navigator.usb.getDevices', prerendering: false}, ]; assert_equals(result.length, expected.length); for (let i = 0; i < result.length; i++) { assert_equals(result[i].event, expected[i].event, `event[${i}]`); assert_equals(result[i].prerendering, expected[i].prerendering, `prerendering[${i}]`); } bc.close(); // Send a close signal to PrerenderEventCollector on the prerendered page. new PrerenderChannel('close', uid).postMessage(''); }, `the access to the Web USB API should be deferred until the prerendered page is activated`); </script> </body>