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

Source/core/accessibility/AccessibilityMenuList.cpp

 /*
  * Copyright (C) 2010 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 88 matching lines @@
 {
     RefPtr<Document> document = &m_renderer->document();
     AXObjectCache* cache = document->axObjectCache();
 
     const AccessibilityChildrenVector& childObjects = children();
     if (!childObjects.isEmpty()) {
         ASSERT(childObjects.size() == 1);
         ASSERT(childObjects[0]->isMenuListPopup());
 
         if (childObjects[0]->isMenuListPopup()) {
-            if (AccessibilityMenuListPopup* popup = static_cast<AccessibilityMenuListPopup*>(childObjects[0].get()))
+            if (AccessibilityMenuListPopup* popup = toAccessibilityMenuListPopup(childObjects[0].get()))
                 popup->didUpdateActiveOption(optionIndex);
         }
     }
 
     cache->postNotification(this, document.get(), AXObjectCache::AXMenuListValueChanged, true, PostSynchronously);
 }
 
 } // namespace WebCore