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

Source/core/accessibility/AXObject.h

 /*
  * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * 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.
@@ skipping 519 matching lines @@
     virtual void setSelected(bool) { }
     void setSelectedText(const String&) { }
     virtual void setSelectedTextRange(const PlainTextRange&) { }
     virtual void setValue(const String&) { }
     virtual void setValue(float) { }
 
     // Notifications that this object may have changed.
     virtual void childrenChanged() { }
     virtual void handleActiveDescendantChanged() { }
     virtual void handleAriaExpandedChanged() { }
-    void notifyIfIgnoredValueChanged();
+    bool notifyIfIgnoredValueChanged();
     virtual void selectionChanged();
     virtual void textChanged() { }
     virtual void updateAccessibilityRole() { }
 
     // Text metrics. Most of these should be deprecated, needs major cleanup.
     virtual VisiblePosition visiblePositionForIndex(int) const { return VisiblePosition(); }
     int lineForPosition(const VisiblePosition&) const;
     virtual int index(const VisiblePosition&) const { return -1; }
     virtual void lineBreaks(Vector<int>&) const { }
 
@@ skipping 24 matching lines @@
 
     bool m_detached;
 };
 
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, object.predicate)
 
 } // namespace WebCore
 
 #endif // AXObject_h