Bug 1648468 - Part 6 - Resolve a11y focus issue causing a failure in browser_test_focus_urlbar.js. r=adw

The line that adds `suggestedIndex` in the test should also fix bug 1652138.

Differential Revision: https://phabricator.services.mozilla.com/D83244

accessible/tests/browser/events/browser_test_focus_urlbar.js

@@ -337,6 +337,9 @@ async function runTipTests() {
     ),
   ];
 
+  // Ensure the tip appears in the expected position.
+  matches[1].suggestedIndex = 2;
+
   let provider = new TipTestProvider(matches);
   UrlbarProvidersManager.registerProvider(provider);
 

browser/components/urlbar/UrlbarView.jsm

@@ -547,6 +547,18 @@ class UrlbarView {
       });
     }
 
+    // If we update the selected element, a new unique ID is generated for it.
+    // We need to ensure that aria-activedescendant reflects this new ID.
+    if (this.selectedElement && !this.oneOffSearchButtons.selectedButton) {
+      let aadID = this.input.inputField.getAttribute("aria-activedescendant");
+      if (!aadID) {
+        Cu.reportError("Selected element but no aria-activedescendant!");
+        this._setAccessibleFocus(this.selectedElement);
+      } else if (!this.document.getElementById(aadID)) {
+        this._setAccessibleFocus(this.selectedElement);
+      }
+    }
+
     this._openPanel();
 
     if (firstResult.heuristic) {