Revert "Implement proposed shadow tree cascade order."

Source/core/css/resolver/ScopedStyleResolver.cpp

Index: Source/core/css/resolver/ScopedStyleResolver.cpp
diff --git a/Source/core/css/resolver/ScopedStyleResolver.cpp b/Source/core/css/resolver/ScopedStyleResolver.cpp
index 6fe45475d5fb768278ca36fde453017d9ef2bee9..fc915a2639266b5f8858b0e1b481a05fc1801714 100644
--- a/Source/core/css/resolver/ScopedStyleResolver.cpp
+++ b/Source/core/css/resolver/ScopedStyleResolver.cpp
@@ -169,18 +169,10 @@ void ScopedStyleResolver::collectMatchingShadowHostRules(ElementRuleCollector& c
 
 void ScopedStyleResolver::collectMatchingTreeBoundaryCrossingRules(ElementRuleCollector& collector, bool includeEmptyRules, CascadeOrder cascadeOrder)
 {
-    if (!m_treeBoundaryCrossingRuleSet)
-        return;
-
-    ASSERT(!collector.scopeContainsLastMatchedElement());
-    collector.setScopeContainsLastMatchedElement(true);
-
     for (const auto& rules : *m_treeBoundaryCrossingRuleSet) {
         MatchRequest request(rules->m_ruleSet.get(), includeEmptyRules, &treeScope().rootNode(), rules->m_parentStyleSheet, rules->m_parentIndex);
         collector.collectMatchingRules(request, cascadeOrder, true);
     }
-
-    collector.setScopeContainsLastMatchedElement(false);
 }
 
 void ScopedStyleResolver::matchPageRules(PageRuleCollector& collector)