Make sendPings accommodate any context node.

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 1745 matching lines @@
     Node* rootNode = const_cast<Node*>(this);
     while (parentOrShadowHostOrFrameOwner(rootNode))
         rootNode = parentOrShadowHostOrFrameOwner(rootNode);
     showSubTreeAcrossFrame(rootNode, this, "");
 }
 
 #endif
 
 // --------
 
-Element* Node::enclosingLinkEventParentOrSelf()
+Element* Node::enclosingLinkEventParentOrSelf() const
 {
-    for (Node* node = this; node; node = ComposedTreeTraversal::parent(*node)) {
+    for (Node* node = const_cast<Node*>(this); node; node = ComposedTreeTraversal::parent(*node)) {
         // For imagemaps, the enclosing link node is the associated area element not the image itself.
         // So we don't let images be the enclosingLinkNode, even though isLink sometimes returns true
         // for them.
         if (node->isLink() && !isHTMLImageElement(*node)) {
             // Casting to Element is safe because only HTMLAnchorElement, HTMLImageElement and
             // SVGAElement can return true for isLink().
             return toElement(node);
         }
     }
 
@@ skipping 686 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif