Get rid of TreeBoundaryCrossingRules.

Source/core/dom/StyleEngine.h

Index: Source/core/dom/StyleEngine.h
diff --git a/Source/core/dom/StyleEngine.h b/Source/core/dom/StyleEngine.h
index dca65687e8cc25f9401a9695415110fbcf6a98d4..ff70047040bfcfb037c129c05a2a21a15d19ed6a 100644
--- a/Source/core/dom/StyleEngine.h
+++ b/Source/core/dom/StyleEngine.h
@@ -124,6 +124,10 @@ public:
     bool usesRemUnits() const { return m_usesRemUnits; }
     void setUsesRemUnit(bool b) { m_usesRemUnits = b; }
 
+    bool hasTreeBoundaryCrossingRules() const { return m_treeBoundaryCrossingScopeCount; }
+    void addTreeBoundaryCrossingScope() { ++m_treeBoundaryCrossingScopeCount; }
+    void removeTreeBoundaryCrossingScope() { --m_treeBoundaryCrossingScopeCount; }
+
     void combineCSSFeatureFlags(const RuleFeatureSet&);
     void resetCSSFeatureFlags(const RuleFeatureSet&);
 
@@ -293,7 +297,7 @@ private:
     bool m_usesFirstLetterRules;
     bool m_usesRemUnits;
     unsigned m_maxDirectAdjacentSelectors;
-
+    unsigned m_treeBoundaryCrossingScopeCount;
     bool m_ignorePendingStylesheets;
     bool m_didCalculateResolver;
     OwnPtrWillBeMember<StyleResolver> m_resolver;