Make Element::elementData() / ensureUniqueElementData() protected

Source/core/css/resolver/SharedStyleFinder.cpp

Index: Source/core/css/resolver/SharedStyleFinder.cpp
diff --git a/Source/core/css/resolver/SharedStyleFinder.cpp b/Source/core/css/resolver/SharedStyleFinder.cpp
index 789c7315cea5feb60adbd9b5eade79c0928d9ffb..71da2999db5788f78f494f1d4d2c02bd7122dfd5 100644
--- a/Source/core/css/resolver/SharedStyleFinder.cpp
+++ b/Source/core/css/resolver/SharedStyleFinder.cpp
@@ -116,7 +116,7 @@ static inline const AtomicString& typeAttributeValue(const Element& element)
 
 bool SharedStyleFinder::sharingCandidateHasIdenticalStyleAffectingAttributes(Element& candidate) const
 {
-    if (element().elementData() == candidate.elementData())
+    if (element().sharesSameElementData(candidate))
         return true;
     if (element().fastGetAttribute(XMLNames::langAttr) != candidate.fastGetAttribute(XMLNames::langAttr))
         return false;