Add hack so VoiceOver speaks updates to injected live regions.

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/logging.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
+#import "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/common/accessibility_messages.h"
 
 namespace content {
 
 // static
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     const ui::AXTreeUpdate& initial_tree,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManagerMac(
       NULL, initial_tree, delegate, factory);
 }
 
 BrowserAccessibilityManagerMac::BrowserAccessibilityManagerMac(
     NSView* parent_view,
     const ui::AXTreeUpdate& initial_tree,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory)
     : BrowserAccessibilityManager(initial_tree, delegate, factory),
-      parent_view_(parent_view) {
+      parent_view_(parent_view),
+      created_live_region_(false) {
 }
 
 // static
 ui::AXTreeUpdate BrowserAccessibilityManagerMac::GetEmptyDocument() {
   ui::AXNodeData empty_document;
   empty_document.id = 0;
   empty_document.role = ui::AX_ROLE_ROOT_WEB_AREA;
   empty_document.state =
       1 << ui::AX_STATE_READ_ONLY;
   ui::AXTreeUpdate update;
@@ skipping 108 matching lines @@
       return;
     default:
       LOG(WARNING) << "Unknown accessibility event: " << event_type;
       return;
   }
   BrowserAccessibilityCocoa* native_node = node->ToBrowserAccessibilityCocoa();
   DCHECK(native_node);
   NSAccessibilityPostNotification(native_node, event_id);
 }
 
+void BrowserAccessibilityManagerMac::OnNodeCreationFinished(ui::AXNode* node) {
+  BrowserAccessibility* obj = GetFromAXNode(node);
+  if (obj && obj->HasStringAttribute(ui::AX_ATTR_LIVE_STATUS))
+    created_live_region_ = true;
+}
+
+void BrowserAccessibilityManagerMac::OnTreeUpdateFinished() {
+  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());
+  root->RecreateNativeObject();
+  NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, root);
+
+  created_live_region_ = false;
+}
+
 }  // namespace content