Made a generator for .h files for implementations of CSSPropertyAPI.h

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWillChange.h

-// Copyright 2016 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 CSSPropertyAPIWillChange_h
-#define CSSPropertyAPIWillChange_h
-
-#include "core/CSSPropertyNames.h"
-#include "core/css/parser/CSSPropertyParser.h"
-#include "core/css/properties/CSSPropertyAPI.h"
-
-namespace blink {
-
-class CSSParserTokenRange;
-class CSSParserContext;
-
-class CSSPropertyAPIWillChange : public CSSPropertyAPI {
- public:
-  static const CSSValue* parseSingleValue(CSSParserTokenRange&,
-                                          const CSSParserContext&);
-};
-
-}  // namespace blink
-
-#endif  // CSSPropertyAPIWillChange_h