Make sendPings accommodate any context node.

Source/core/dom/Node.h

Index: Source/core/dom/Node.h
diff --git a/Source/core/dom/Node.h b/Source/core/dom/Node.h
index 2af161a3a06feea15fa8953cc2da328fc65151e5..52212cbb4bae6e6adbf326c5d0d915399d815a2e 100644
--- a/Source/core/dom/Node.h
+++ b/Source/core/dom/Node.h
@@ -316,7 +316,7 @@ public:
     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; }