Port Node's previousElementSibling() / nextElementSibling() to ElementTraversal

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index aca59a4afa58d34bff2a3bea944423b84fd46f69..f81b2c47e7c27119654fa368aa4a39936cd55ea0 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -41,6 +41,7 @@
 #include "core/dom/DocumentType.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementRareData.h"
+#include "core/dom/ElementTraversal.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/LiveNodeList.h"
 #include "core/dom/NodeRareData.h"
@@ -2548,6 +2549,16 @@ void Node::setCustomElementState(CustomElementState newState)
         setNeedsStyleRecalc(SubtreeStyleChange); // :unresolved has changed
 }
 
+Element* Node::previousElementSibling() const
+{
+    return ElementTraversal::previousSibling(*this);
+}
+
+Element* Node::nextElementSibling() const
+{
+    return ElementTraversal::nextSibling(*this);
+}
+
 } // namespace WebCore
 
 #ifndef NDEBUG