Update the accessibility tree when a modal dialog is opened/closed.

Source/core/accessibility/AXObjectCache.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 104 matching lines @@
     void childrenChanged(AXObject*);
     void checkedStateChanged(Node*);
     void selectedChildrenChanged(Node*);
     void selectedChildrenChanged(RenderObject*);
     void selectionChanged(Node*);
     // Called by a node when text or a text equivalent (e.g. alt) attribute is changed.
     void textChanged(Node*);
     void textChanged(RenderObject*);
     // Called when a node has just been attached, so we can make sure we have the right subclass of AXObject.
     void updateCacheAfterNodeIsAttached(Node*);
+    // Called when a modal dialog opens or closes, which may cause nodes all over the tree to become inert or not inert.
+    void handleInertSubtreesChanged();
 
     void handleActiveDescendantChanged(Node*);
     void handleAriaRoleChanged(Node*);
     void handleFocusedUIElementChanged(Node* oldFocusedNode, Node* newFocusedNode);
     void handleScrolledToAnchor(const Node* anchorNode);
     void handleAriaExpandedChange(Node*);
     void handleScrollbarUpdate(ScrollView*);
 
     void handleAttributeChanged(const QualifiedName& attrName, Element*);
     void recomputeIsIgnored(RenderObject* renderer);
@@ skipping 91 matching lines @@
     AXID getAXID(AXObject*);
 };
 
 bool nodeHasRole(Node*, const String& role);
 // This will let you know if aria-hidden was explicitly set to false.
 bool isNodeAriaVisible(Node*);
 
 }
 
 #endif