Pass implementation object to supplemental classes by reference

Source/core/dom/ParentNode.h

 /*
  * Copyright (C) 2013 Samsung Electronics. 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 20 matching lines @@
 #ifndef ParentNode_h
 #define ParentNode_h
 
 #include "core/dom/ContainerNode.h"
 #include "core/dom/ElementTraversal.h"
 
 namespace WebCore {
 
 class ParentNode {
 public:
-    static PassRefPtr<HTMLCollection> children(ContainerNode* node)
+    static PassRefPtr<HTMLCollection> children(ContainerNode& node)
     {
-        return node->children();
+        return node.children();
     }
 
-    static Element* firstElementChild(ContainerNode* node)
+    static Element* firstElementChild(ContainerNode& node)
     {
-        ASSERT(node);
-        return ElementTraversal::firstWithin(*node);
+        return ElementTraversal::firstWithin(node);
     }
 
-    static Element* lastElementChild(ContainerNode* node)
+    static Element* lastElementChild(ContainerNode& node)
     {
-        ASSERT(node);
-        return ElementTraversal::lastWithin(*node);
+        return ElementTraversal::lastWithin(node);
     }
 
-    static unsigned childElementCount(ContainerNode* node)
+    static unsigned childElementCount(ContainerNode& node)
     {
-        ASSERT(node);
         unsigned count = 0;
-        for (Element* child = ElementTraversal::firstWithin(*node); child; child = ElementTraversal::nextSibling(*child))
+        for (Element* child = ElementTraversal::firstWithin(node); child; child = ElementTraversal::nextSibling(*child))
             ++count;
         return count;
     }
 };
 
 } // namespace WebCore
 
 #endif // ParentNode_h