Get rid of postToElement argument for accessibility notifications.

Source/modules/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 539 matching lines @@
     virtual AXObject* nextSibling() const { return 0; }
     AXObject* firstAccessibleObjectFromNode(const Node*);
     virtual void addChildren() { }
     virtual bool canHaveChildren() const { return true; }
     bool hasChildren() const { return m_haveChildren; }
     virtual void updateChildrenIfNecessary();
     virtual bool needsToUpdateChildren() const { return false; }
     virtual void setNeedsToUpdateChildren() { }
     virtual void clearChildren();
     virtual void detachFromParent() { m_parent = 0; }
-    virtual AXObject* observableObject() const { return 0; }
     virtual AXObject* scrollBar(AccessibilityOrientation) { return 0; }
 
     // Properties of the object's owning document or page.
     virtual double estimatedLoadingProgress() const { return 0; }
     AXObject* focusedUIElement() const;
 
     // DOM and layout tree access.
     virtual Node* node() const { return 0; }
     virtual LayoutObject* layoutObject() const { return 0; }
     virtual Document* document() const;
@@ skipping 90 matching lines @@
     static bool includesARIAWidgetRole(const String&);
     static bool hasInteractiveARIAAttribute(const Element&);
 };
 
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, object.predicate)
 
 } // namespace blink
 
 #endif // AXObject_h