1 files changed, 54 insertions, 0 deletions
diff --git a/gfx/tests/browser/browser_windowless_troubleshoot_crash.js b/gfx/tests/browser/browser_windowless_troubleshoot_crash.js
new file mode 100644
index 0000000000..44fc50e2f8
--- /dev/null
+++ b/gfx/tests/browser/browser_windowless_troubleshoot_crash.js
@@ -0,0 +1,54 @@
+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();
+});