Move some Element specific code from Node::detach to Element::detach.

Source/core/dom/UserActionElementSet.h

 /*
  * Copyright (C) 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 34 matching lines @@
     bool isInActiveChain(const Node* node) { return hasFlags(node, InActiveChainFlag); }
     bool isHovered(const Node* node) { return hasFlags(node, IsHoveredFlag); }
     void setFocused(Node* node, bool enable) { setFlags(node, enable, IsFocusedFlag); }
     void setActive(Node* node, bool enable) { setFlags(node, enable, IsActiveFlag); }
     void setInActiveChain(Node* node, bool enable) { setFlags(node, enable, InActiveChainFlag); }
     void setHovered(Node* node, bool enable) { setFlags(node, enable, IsHoveredFlag); }
 
     UserActionElementSet();
     ~UserActionElementSet();
 
-    void didDetach(Node*);
+    void didDetach(Element&);
 
 #if !ENABLE(OILPAN)
     void documentDidRemoveLastRef();
 #endif
 
     DECLARE_TRACE();
 
 private:
     enum ElementFlags {
         IsActiveFlag      = 1 ,
@@ skipping 11 matching lines @@
     void clearFlags(Element*, unsigned);
     bool hasFlags(const Element*, unsigned flags) const;
 
     typedef WillBeHeapHashMap<RefPtrWillBeMember<Element>, unsigned> ElementFlagMap;
     ElementFlagMap m_elements;
 };
 
 } // namespace
 
 #endif // UserActionElementSet_h