add_task(async function test_windowlessBrowserTroubleshootCrash() { let webNav = Services.appShell.createWindowlessBrowser(false); let onLoaded = new Promise((resolve, reject) => { let docShell = webNav.docShell; let listener = { observe(contentWindow, topic, data) { let observedDocShell = contentWindow.docShell.sameTypeRootTreeItem.QueryInterface( Ci.nsIDocShell ); if (docShell === observedDocShell) { Services.obs.removeObserver( listener, "content-document-global-created" ); resolve(); } }, }; Services.obs.addObserver(listener, "content-document-global-created"); }); let loadURIOptions = { triggeringPrincipal: Services.scriptSecurityManager.createNullPrincipal({}), }; webNav.loadURI(Services.io.newURI("about:blank"), loadURIOptions); await onLoaded; let winUtils = webNav.document.defaultView.windowUtils; try { let layerManager = winUtils.layerManagerType; ok( layerManager == "Basic" || layerManager == "WebRender (Software)", "windowless browser's layerManagerType should be 'Basic' or 'WebRender (Software)'" ); } catch (e) { // The windowless browser may not have a layermanager at all yet, and that's ok. // The troubleshooting code similarly skips over windows with no layer managers. } ok(true, "not crashed"); var { Troubleshoot } = ChromeUtils.importESModule( "resource://gre/modules/Troubleshoot.sys.mjs" ); var data = await Troubleshoot.snapshot(); ok( data.graphics.windowLayerManagerType !== "None", "windowless browser window should not set windowLayerManagerType to 'None'" ); webNav.close(); });