Bug 1671049 - Invalidate cached ARIA role and role in mozAccessible when role changes. r=morgan

Besides the ARIA role invalidation, this fixes an issue where the mozAccessible's role is also incorrect when the aria role changes on a body tag.

Depends on D93439

Differential Revision: https://phabricator.services.mozilla.com/D93440

accessible/base/Platform.h

@@ -15,6 +15,10 @@
 #  include "nsRect.h"
 #endif
 
+#ifdef MOZ_WIDGET_COCOA
+#  include "mozilla/a11y/Role.h"
+#endif
+
 namespace mozilla {
 namespace a11y {
 
@@ -142,6 +146,8 @@ bool LocalizeString(
 class TextRangeData;
 void ProxyTextSelectionChangeEvent(ProxyAccessible* aTarget,
                                    const nsTArray<TextRangeData>& aSelection);
+
+void ProxyRoleChangedEvent(ProxyAccessible* aTarget, const a11y::role& aRole);
 #endif
 
 }  // namespace a11y

accessible/ipc/DocAccessibleParent.cpp

@@ -530,6 +530,11 @@ mozilla::ipc::IPCResult DocAccessibleParent::RecvRoleChangedEvent(
   }
 
   mRole = aRole;
+
+#ifdef MOZ_WIDGET_COCOA
+  ProxyRoleChangedEvent(this, aRole);
+#endif
+
   return IPC_OK();
 }
 

accessible/mac/Platform.mm

@@ -161,6 +161,12 @@ void ProxyTextSelectionChangeEvent(ProxyAccessible* aTarget,
   }
 }
 
+void ProxyRoleChangedEvent(ProxyAccessible* aTarget, const a11y::role& aRole) {
+  if (mozAccessible* wrapper = GetNativeFromGeckoAccessible(aTarget)) {
+    [wrapper handleRoleChanged:aRole];
+  }
+}
+
 }  // namespace a11y
 }  // namespace mozilla
 

accessible/mac/mozAccessible.h

@@ -106,6 +106,9 @@ inline mozAccessible* GetNativeFromGeckoAccessible(
 // Get top level (tab) web area.
 - (mozAccessible*)topWebArea;
 
+// Handle a role change
+- (void)handleRoleChanged:(mozilla::a11y::role)newRole;
+
 #pragma mark - mozAccessible protocol / widget
 
 // override

accessible/mac/mozAccessible.mm

@@ -779,6 +779,14 @@ struct RoleDescrComparator {
   return nil;
 }
 
+- (void)handleRoleChanged:(mozilla::a11y::role)newRole {
+  mRole = newRole;
+  mARIARole = nullptr;
+
+  // For testing purposes
+  [self moxPostNotification:@"AXMozRoleChanged"];
+}
+
 - (id)moxEditableAncestor {
   for (id element = self; [element conformsToProtocol:@protocol(MOXAccessible)];
        element = [element moxUnignoredParent]) {

accessible/tests/browser/mac/browser_roles_elements.js

@@ -202,3 +202,21 @@ addAccessibleTask(
     );
   }
 );
+
+addAccessibleTask(`<button>hello world</button>`, async (browser, accDoc) => {
+  const webArea = accDoc.nativeInterface.QueryInterface(
+    Ci.nsIAccessibleMacInterface
+  );
+
+  is(webArea.getAttributeValue("AXRole"), "AXWebArea");
+  is(webArea.getAttributeValue("AXSubrole"), "AXUnknown");
+
+  let roleChanged = waitForMacEvent("AXMozRoleChanged");
+  await SpecialPowers.spawn(browser, [], () => {
+    content.document.body.setAttribute("role", "application");
+  });
+  await roleChanged;
+
+  is(webArea.getAttributeValue("AXRole"), "AXGroup");
+  is(webArea.getAttributeValue("AXSubrole"), "AXLandmarkApplication");
+});