Switching CSS Variables over to RuntimeEnabledFeatures

Source/core/page/Settings.h

Index: Source/core/page/Settings.h
diff --git a/Source/core/page/Settings.h b/Source/core/page/Settings.h
index 7ef12c80fd873454a40ddfbf68988d005cf6485d..c8775ca8407f494c5671d9a4bb6cf1e55a469acb 100644
--- a/Source/core/page/Settings.h
+++ b/Source/core/page/Settings.h
@@ -148,9 +148,6 @@ public:
     void setCSSStickyPositionEnabled(bool enabled) { m_cssStickyPositionEnabled = enabled; }
     bool cssStickyPositionEnabled() const { return m_cssStickyPositionEnabled; }
 
-    void setCSSVariablesEnabled(bool enabled) { m_cssVariablesEnabled = enabled; }
-    bool cssVariablesEnabled() const { return m_cssVariablesEnabled; }
-
     static void setMockScrollbarsEnabled(bool flag);
     static bool mockScrollbarsEnabled();
 
@@ -191,7 +188,6 @@ private:
     unsigned m_fontRenderingMode : 1;
     bool m_isCSSCustomFilterEnabled : 1;
     bool m_cssStickyPositionEnabled : 1;
-    bool m_cssVariablesEnabled : 1;
     bool m_dnsPrefetchingEnabled : 1;
 
     bool m_touchEventEmulationEnabled : 1;