Revert "Replace style sharing cousin list search with LRU"

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 23439a09e3c2564f1af3fbc884d7238757882f04..318ced439f0281f06f6538befdd02dd98b357892 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -1760,10 +1760,8 @@ void Document::recalcStyle(StyleRecalcChange change)
         m_inStyleRecalc = false;
 
         // Pseudo element removal and similar may only work with these flags still set. Reset them after the style recalc.
-        if (m_styleResolver) {
+        if (m_styleResolver)
             m_styleSheetCollections->resetCSSFeatureFlags(m_styleResolver->ruleFeatureSet());
-            m_styleResolver->clearStyleSharingList();
-        }
 
         if (frameView) {
             frameView->resumeScheduledEvents();
@@ -2049,8 +2047,6 @@ void Document::detach(const AttachContext& context)
 
     unscheduleStyleRecalc();
 
-    clearStyleResolver();
-
     if (render)
         render->destroy();