Add const versions of some toHTMLFooElement().

Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1988 matching lines @@
         parent = node->document().frame()->ownerElement();
     return parent;
 }
 
 static void showSubTreeAcrossFrame(const Node* node, const Node* markedNode, const String& indent)
 {
     if (node == markedNode)
         fputs("*", stderr);
     fputs(indent.utf8().data(), stderr);
     node->showNode();
-     if (node->isShadowRoot()) {
-         if (ShadowRoot* youngerShadowRoot = toShadowRoot(node)->youngerShadowRoot())
-             showSubTreeAcrossFrame(youngerShadowRoot, markedNode, indent + "\t");
-     } else {
-         if (node->isFrameOwnerElement())
-             showSubTreeAcrossFrame(static_cast<const HTMLFrameOwnerElement*>(node)->contentDocument(), markedNode, indent + "\t");
-         if (ShadowRoot* oldestShadowRoot = oldestShadowRootFor(node))
-             showSubTreeAcrossFrame(oldestShadowRoot, markedNode, indent + "\t");
-     }
+    if (node->isShadowRoot()) {
+        if (ShadowRoot* youngerShadowRoot = toShadowRoot(node)->youngerShadowRoot())
+            showSubTreeAcrossFrame(youngerShadowRoot, markedNode, indent + "\t");
+    } else {
+        if (node->isFrameOwnerElement())
+            showSubTreeAcrossFrame(toHTMLFrameOwnerElement(node)->contentDocument(), markedNode, indent + "\t");
+        if (ShadowRoot* oldestShadowRoot = oldestShadowRootFor(node))
+            showSubTreeAcrossFrame(oldestShadowRoot, markedNode, indent + "\t");
+    }
     for (Node* child = node->firstChild(); child; child = child->nextSibling())
         showSubTreeAcrossFrame(child, markedNode, indent + "\t");
 }
 
 void Node::showTreeForThisAcrossFrame() const
 {
     Node* rootNode = const_cast<Node*>(this);
     while (parentOrShadowHostOrFrameOwner(rootNode))
         rootNode = parentOrShadowHostOrFrameOwner(rootNode);
     showSubTreeAcrossFrame(rootNode, this, "");
@@ skipping 675 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif