CSS Custom Properties (Variables)

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 eb10fb5abdad21a6405c5245b235ed4dfaca338d..c8add58967674afeedae828408605b3ff2f935c0 100644
--- a/Source/core/dom/StyleEngine.h
+++ b/Source/core/dom/StyleEngine.h
@@ -121,6 +121,8 @@ public:
 
     bool usesRemUnits() const { return m_usesRemUnits; }
     void setUsesRemUnit(bool b) { m_usesRemUnits = b; }
+    bool usesVariables() const { return m_usesVariables; }
+    void setUsesVariables(bool b) { m_usesVariables = b; }
 
     void combineCSSFeatureFlags(const RuleFeatureSet&);
     void resetCSSFeatureFlags(const RuleFeatureSet&);
@@ -247,6 +249,7 @@ private:
     bool m_usesFirstLineRules;
     bool m_usesWindowInactiveSelector;
     bool m_usesRemUnits;
+    bool m_usesVariables;
     unsigned m_maxDirectAdjacentSelectors;
 
     bool m_ignorePendingStylesheets;