Revert "CSS Custom Properties (Variables)"

third_party/WebKit/Source/core/style/StyleVariableData.h

-#ifndef StyleVariableData_h
-#define StyleVariableData_h
-
-#include "core/css/CSSVariableData.h"
-#include "wtf/Forward.h"
-#include "wtf/HashMap.h"
-#include "wtf/RefCounted.h"
-#include "wtf/text/AtomicStringHash.h"
-
-namespace blink {
-
-class StyleVariableData : public RefCounted<StyleVariableData> {
-public:
-    static PassRefPtr<StyleVariableData> create() { return adoptRef(new StyleVariableData()); }
-    PassRefPtr<StyleVariableData> copy() const { return adoptRef(new StyleVariableData(*this)); }
-
-    bool operator==(const StyleVariableData& other) const { return other.m_data == m_data; }
-    bool operator!=(const StyleVariableData& other) const { return !(*this == other); }
-
-    void setVariable(const AtomicString& name, PassRefPtr<CSSVariableData> value) { m_data.set(name, value); }
-    CSSVariableData* getVariable(const AtomicString& name) const { return m_data.get(name); }
-    void removeVariable(const AtomicString& name) { return m_data.remove(name); }
-private:
-    StyleVariableData() = default;
-    StyleVariableData(const StyleVariableData& other) : RefCounted<StyleVariableData>(), m_data(other.m_data) { }
-
-    friend class CSSVariableResolver;
-
-    HashMap<AtomicString, RefPtr<CSSVariableData>> m_data;
-};
-
-} // namespace blink
-
-#endif // StyleVariableData_h