Bug 1687480 - Fire NSAccessibility notifications for expanding and collapsing rows, r=morgan

Differential Revision: https://phabricator.services.mozilla.com/D102308

accessible/mac/mozTableAccessible.h

@@ -159,4 +159,7 @@
 // override
 - (NSString*)moxLabel;
 
+// override
+- (void)stateChanged:(uint64_t)state isEnabled:(BOOL)enabled;
+
 @end

accessible/mac/mozTableAccessible.mm

@@ -576,4 +576,16 @@ using namespace mozilla::a11y;
   return nsCocoaUtils::ToNSString(title);
 }
 
+- (void)stateChanged:(uint64_t)state isEnabled:(BOOL)enabled {
+  [super stateChanged:state isEnabled:enabled];
+
+  if (state == states::EXPANDED) {
+    // If the EXPANDED state is updated, fire appropriate events on the
+    // outline row.
+    [self moxPostNotification:(enabled
+                                   ? NSAccessibilityRowExpandedNotification
+                                   : NSAccessibilityRowCollapsedNotification)];
+  }
+}
+
 @end

accessible/tests/browser/mac/browser_outline.js

@@ -30,7 +30,7 @@ addAccessibleTask(
         </li>
       </ul>
     </li>
-    <li role="treeitem" aria-expanded="false">
+    <li id="vegetables" role="treeitem" aria-expanded="false">
       <span>
         Vegetables
       </span>
@@ -140,6 +140,32 @@ addAccessibleTask(
       1,
       "Row is level one"
     );
+
+    let evt = waitForMacEvent("AXRowExpanded", "vegetables");
+    await SpecialPowers.spawn(browser, [], () => {
+      content.document
+        .getElementById("vegetables")
+        .setAttribute("aria-expanded", "true");
+    });
+    await evt;
+    is(
+      outRows[2].getAttributeValue("AXDisclosing"),
+      1,
+      "Row is disclosing after being expanded"
+    );
+
+    evt = waitForMacEvent("AXRowCollapsed", "vegetables");
+    await SpecialPowers.spawn(browser, [], () => {
+      content.document
+        .getElementById("vegetables")
+        .setAttribute("aria-expanded", "false");
+    });
+    await evt;
+    is(
+      outRows[2].getAttributeValue("AXDisclosing"),
+      0,
+      "Row is not disclosing after being collapsed again"
+    );
   }
 );