Make sendPings accommodate any context node.

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 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
  * License as published by the Free Software Foundation; either
@@ skipping 298 matching lines @@
     Element* parentOrShadowHostElement() const;
     void setParentOrShadowHostNode(ContainerNode*);
 
     // Knows about all kinds of hosts.
     ContainerNode* parentOrShadowHostOrTemplateHostNode() const;
 
     // Returns the parent node, but nullptr if the parent node is a ShadowRoot.
     ContainerNode* nonShadowBoundaryParentNode() const;
 
     // Returns the enclosing event parent Element (or self) that, when clicked, would trigger a navigation.
-    Element* enclosingLinkEventParentOrSelf();
+    Element* enclosingLinkEventParentOrSelf() const;
 
     // These low-level calls give the caller responsibility for maintaining the integrity of the tree.
     void setPreviousSibling(Node* previous) { m_previous = previous; }
     void setNextSibling(Node* next) { m_next = next; }
 
     virtual bool canContainRangeEndPoint() const { return false; }
 
     // FIXME: These two functions belong in editing -- "atomic node" is an editing concept.
     Node* previousNodeConsideringAtomicNodes() const;
     Node* nextNodeConsideringAtomicNodes() const;
@@ skipping 587 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif // Node_h