Bug 1648813: Wait for AXLoadComplete on spawned tab based on label r=eeejay

Differential Revision: https://phabricator.services.mozilla.com/D104553

accessible/tests/browser/mac/browser_webarea.js

@@ -9,7 +9,9 @@ loadScripts({ name: "role.js", dir: MOCHITESTS_DIR });
 
 // Test web area role and AXLoadComplete event
 addAccessibleTask(``, async (browser, accDoc) => {
-  let evt = waitForMacEvent("AXLoadComplete");
+  let evt = waitForMacEvent("AXLoadComplete", (iface, data) => {
+    return iface.getAttributeValue("AXDescription") == "webarea test";
+  });
   await SpecialPowers.spawn(browser, [], () => {
     content.location = "data:text/html,<title>webarea test</title>";
   });
@@ -22,11 +24,6 @@ addAccessibleTask(``, async (browser, accDoc) => {
   );
   is(doc.getAttributeValue("AXValue"), "", "document has no AXValue");
   is(doc.getAttributeValue("AXTitle"), null, "document has no AXTitle");
-  is(
-    doc.getAttributeValue("AXDescription"),
-    "webarea test",
-    "test has correct label"
-  );
 
   is(doc.getAttributeValue("AXLoaded"), 1, "document has finished loading");
 });