Newly created live regions should fire a private notification on the Mac.

content/browser/accessibility/browser_accessibility_manager_mac.mm

Index: content/browser/accessibility/browser_accessibility_manager_mac.mm
diff --git a/content/browser/accessibility/browser_accessibility_manager_mac.mm b/content/browser/accessibility/browser_accessibility_manager_mac.mm
index 604e42008faa45669f06517fad947ed8f2c832f0..72c25b0c301cd2a5cd23dbd781873f4c7ebc5655 100644
--- a/content/browser/accessibility/browser_accessibility_manager_mac.mm
+++ b/content/browser/accessibility/browser_accessibility_manager_mac.mm
@@ -65,6 +65,8 @@ NSString* const NSAccessibilityLoadCompleteNotification =
     @"AXLoadComplete";
 NSString* const NSAccessibilityInvalidStatusChangedNotification =
     @"AXInvalidStatusChanged";
+NSString* const NSAccessibilityLiveRegionCreatedNotification =
+    @"AXLiveRegionCreated";
 NSString* const NSAccessibilityLiveRegionChangedNotification =
     @"AXLiveRegionChanged";
 NSString* const NSAccessibilityExpandedChanged =
@@ -261,7 +263,10 @@ void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
         return;
       }
       break;
-    // TODO(nektar): Need to add an event for live region created.
+    case ui::AX_EVENT_ALERT:
+      mac_notification = NSAccessibilityLiveRegionCreatedNotification;
+      // A live region created notification must be followed by a live region
+      // changed notification.
     case ui::AX_EVENT_LIVE_REGION_CHANGED:
       mac_notification = NSAccessibilityLiveRegionChangedNotification;
       break;
@@ -284,7 +289,6 @@ void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
       break;
 
     // These events are not used on Mac for now.
-    case ui::AX_EVENT_ALERT:
     case ui::AX_EVENT_TEXT_CHANGED:
     case ui::AX_EVENT_CHILDREN_CHANGED:
     case ui::AX_EVENT_MENU_LIST_VALUE_CHANGED:
@@ -383,7 +387,8 @@ void BrowserAccessibilityManagerMac::OnAtomicUpdateFinished(
     BrowserAccessibility* obj = GetFromAXNode(changed_node);
     if (obj && obj->HasStringAttribute(ui::AX_ATTR_LIVE_STATUS)) {
       created_live_region = true;
-      break;
+      NotifyAccessibilityEvent(BrowserAccessibilityEvent::FromTreeChange,
+                               ui::AX_EVENT_ALERT, obj);
     }
   }