[Variables] Enable get/setProperty and similar APIs from the CSSOM

third_party/WebKit/Source/core/css/CSSCustomPropertyDeclaration.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CSSCustomPropertyDeclaration_h
 #define CSSCustomPropertyDeclaration_h
 
 #include "core/css/CSSValue.h"
 #include "core/css/CSSVariableData.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class CSSCustomPropertyDeclaration : public CSSValue {
 public:
     static PassRefPtrWillBeRawPtr<CSSCustomPropertyDeclaration> create(const AtomicString& name, PassRefPtr<CSSVariableData> value)
     {
         return adoptRefWillBeNoop(new CSSCustomPropertyDeclaration(name, value));
     }
 
     static PassRefPtrWillBeRawPtr<CSSCustomPropertyDeclaration> create(const AtomicString& name, CSSValueID id)
     {
         return adoptRefWillBeNoop(new CSSCustomPropertyDeclaration(name, id));
     }
 
     const AtomicString& name() const { return m_name; }
     CSSVariableData* value() const { return m_value.get(); }
     CSSValueID id() const { return m_valueId; }
+    String customCSSText() const;
 
     bool equals(const CSSCustomPropertyDeclaration& other) const { return this == &other; }
 
     DECLARE_TRACE_AFTER_DISPATCH();
 private:
     CSSCustomPropertyDeclaration(const AtomicString& name, CSSValueID id)
         : CSSValue(CustomPropertyDeclarationClass)
         , m_name(name)
         , m_value(nullptr)
         , m_valueId(id)
@@ skipping 12 matching lines @@
     const AtomicString m_name;
     RefPtr<CSSVariableData> m_value;
     CSSValueID m_valueId;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSCustomPropertyDeclaration, isCustomPropertyDeclaration());
 
 } // namespace blink
 
 #endif // CSSCustomPropertyDeclaration_h