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

content/browser/accessibility/browser_accessibility_manager_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/browser_accessibility_manager_mac.h"
 
 #import "base/mac/mac_util.h"
 #import "base/mac/sdk_forward_declarations.h"
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 47 matching lines @@
 };
 
 NSString* const NSAccessibilityAutocorrectionOccurredNotification =
     @"AXAutocorrectionOccurred";
 NSString* const NSAccessibilityLayoutCompleteNotification =
     @"AXLayoutComplete";
 NSString* const NSAccessibilityLoadCompleteNotification =
     @"AXLoadComplete";
 NSString* const NSAccessibilityInvalidStatusChangedNotification =
     @"AXInvalidStatusChanged";
+NSString* const NSAccessibilityLiveRegionCreatedNotification =
+    @"AXLiveRegionCreated";
 NSString* const NSAccessibilityLiveRegionChangedNotification =
     @"AXLiveRegionChanged";
 NSString* const NSAccessibilityExpandedChanged =
     @"AXExpandedChanged";
 NSString* const NSAccessibilityMenuItemSelectedNotification =
     @"AXMenuItemSelected";
 
 // Attributes used for NSAccessibilitySelectedTextChangedNotification and
 // NSAccessibilityValueChangedNotification.
 NSString* const NSAccessibilityTextStateChangeTypeKey =
@@ skipping 176 matching lines @@
         if (!root)
           return;
 
         NSAccessibilityPostNotificationWithUserInfo(
             native_node, mac_notification, user_info);
         NSAccessibilityPostNotificationWithUserInfo(
             ToBrowserAccessibilityCocoa(root), mac_notification, user_info);
         return;
       }
       break;
-    // TODO(nektar): Need to add an event for live region created.
+    case ui::AX_EVENT_ALERT:
+      mac_notification = NSAccessibilityLiveRegionCreatedNotification;
+      break;
     case ui::AX_EVENT_LIVE_REGION_CHANGED:
       mac_notification = NSAccessibilityLiveRegionChangedNotification;
       break;
     case ui::AX_EVENT_ROW_COUNT_CHANGED:
       mac_notification = NSAccessibilityRowCountChangedNotification;
       break;
     case ui::AX_EVENT_ROW_EXPANDED:
       mac_notification = NSAccessibilityRowExpandedNotification;
       break;
     case ui::AX_EVENT_ROW_COLLAPSED:
       mac_notification = NSAccessibilityRowCollapsedNotification;
       break;
     // TODO(nektar): Add events for busy.
     case ui::AX_EVENT_EXPANDED_CHANGED:
       mac_notification = NSAccessibilityExpandedChanged;
       break;
     // TODO(nektar): Support menu open/close notifications.
     case ui::AX_EVENT_MENU_LIST_ITEM_SELECTED:
       mac_notification = NSAccessibilityMenuItemSelectedNotification;
       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:
     case ui::AX_EVENT_SCROLL_POSITION_CHANGED:
     case ui::AX_EVENT_SCROLLED_TO_ANCHOR:
     case ui::AX_EVENT_ARIA_ATTRIBUTE_CHANGED:
     case ui::AX_EVENT_LOCATION_CHANGED:
       return;
 
     // Deprecated events.
@@ skipping 68 matching lines @@
   }
 }
 
 void BrowserAccessibilityManagerMac::OnAtomicUpdateFinished(
     ui::AXTree* tree,
     bool root_changed,
     const std::vector<ui::AXTreeDelegate::Change>& changes) {
   BrowserAccessibilityManager::OnAtomicUpdateFinished(
       tree, root_changed, changes);
 
-  bool created_live_region = false;
   for (size_t i = 0; i < changes.size(); ++i) {
     if (changes[i].type != NODE_CREATED && changes[i].type != SUBTREE_CREATED)
       continue;
 
     const ui::AXNode* changed_node = changes[i].node;
     DCHECK(changed_node);
     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);
     }
   }
-
-  if (!created_live_region)
-    return;
-
-  // This code is to work around a bug in VoiceOver, where a new live
-  // region that gets added is ignored. VoiceOver seems to only scan the
-  // page for live regions once. By recreating the NSAccessibility
-  // object for the root of the tree, we force VoiceOver to clear out its
-  // internal state and find newly-added live regions this time.
-  BrowserAccessibilityMac* root =
-      static_cast<BrowserAccessibilityMac*>(GetRoot());
-  if (root) {
-    root->RecreateNativeObject();
-    NotifyAccessibilityEvent(
-        BrowserAccessibilityEvent::FromTreeChange,
-        ui::AX_EVENT_CHILDREN_CHANGED,
-        root);
-  }
 }
 
 NSDictionary* BrowserAccessibilityManagerMac::
     GetUserInfoForSelectedTextChangedNotification() {
   NSMutableDictionary* user_info = [[[NSMutableDictionary alloc] init]
       autorelease];
   [user_info setObject:@YES forKey:NSAccessibilityTextStateSyncKey];
   [user_info setObject:@(AXTextStateChangeTypeUnknown)
                 forKey:NSAccessibilityTextStateChangeTypeKey];
   [user_info setObject:@(AXTextSelectionDirectionUnknown)
@@ skipping 48 matching lines @@
   }
 
   return @{
     NSAccessibilityTextStateChangeTypeKey : @(AXTextStateChangeTypeEdit),
     NSAccessibilityTextChangeValues : changes,
     NSAccessibilityTextChangeElement : native_node
   };
 }
 
 }  // namespace content