Cleanup <static_cast>: Switch to toFoo for Accessibility Objects.

Source/core/accessibility/AccessibilityListBoxOption.h

 /*
  * Copyright (C) 2008 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
@@ skipping 48 matching lines @@
     virtual Node* node() const OVERRIDE { return m_optionElement; }
     virtual void setSelected(bool) OVERRIDE;
     virtual bool canSetSelectedAttribute() const OVERRIDE;
 
     virtual LayoutRect elementRect() const OVERRIDE;
     virtual AccessibilityObject* parentObject() const OVERRIDE;
 
 private:
     HTMLElement* m_optionElement;
 
+    virtual bool isListBoxOption() const OVERRIDE { return true; }
     virtual bool canHaveChildren() const OVERRIDE { return false; }
     virtual bool computeAccessibilityIsIgnored() const OVERRIDE;
 
     HTMLSelectElement* listBoxOptionParentNode() const;
     int listBoxOptionIndex() const;
     AccessibilityObject* listBoxOptionAccessibilityObject(HTMLElement*) const;
 };
 
+inline AccessibilityListBoxOption* toAccessibilityListBoxOption(AccessibilityObject* object)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isListBoxOption());
+    return static_cast<AccessibilityListBoxOption*>(object);
+}
+
+inline const AccessibilityListBoxOption* toAccessibilityListBoxOption(const AccessibilityObject* object)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isListBoxOption());
+    return static_cast<const AccessibilityListBoxOption*>(object);
+}
+
+// This will catch anyone doing an unnecessary cast.
+void toAccessibilityListBoxOption(const AccessibilityListBoxOption*);
+
 } // namespace WebCore
 
 #endif // AccessibilityListBoxOption_h