Replace style sharing cousin list search with LRU

Source/core/css/resolver/SharedStyleFinder.h

Index: Source/core/css/resolver/SharedStyleFinder.h
diff --git a/Source/core/css/resolver/SharedStyleFinder.h b/Source/core/css/resolver/SharedStyleFinder.h
index 7734c3665d7c791366125dffaafe9d9af98d3167..d407279a5884693859594aba02e38b91c2b02e28 100644
--- a/Source/core/css/resolver/SharedStyleFinder.h
+++ b/Source/core/css/resolver/SharedStyleFinder.h
@@ -51,8 +51,7 @@ public:
     RenderStyle* locateSharedStyle(const ElementResolveContext&, RenderStyle* newStyle);
 
 private:
-    Node* locateCousinList(Element* parent, unsigned& visitedNodeCount) const;
-    Element* findSiblingForStyleSharing(const ElementResolveContext&, Node*, unsigned& count) const;
+    Element* findElementForStyleSharing(const ElementResolveContext&) const;
 
     // Only used when we're collecting stats on styles
     Element* searchDocumentForSharedStyle(const ElementResolveContext&) const;