[Oilpan] Prepare full definition of classes before using Member

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

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 
 class CSSRule;
 class CSSValue;
 class Element;
 class ExceptionState;
 class MutableStylePropertySet;
 class StyleSheetContents;
 
 class AbstractPropertySetCSSStyleDeclaration : public CSSStyleDeclaration {
 public:
-    virtual Element* parentElement() const { return 0; }
+    virtual Element* parentElement() const { return nullptr; }
     StyleSheetContents* contextStyleSheet() const;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     CSSRule* parentRule() const override { return 0; }
     unsigned length() const final;
     String item(unsigned index) const final;
     String getPropertyValue(const String& propertyName) final;
     String getPropertyPriority(const String& propertyName) final;
@@ skipping 65 matching lines @@
     void didMutate(MutationType) override;
 
 #if !ENABLE(OILPAN)
     unsigned m_refCount;
 #endif
     RawPtrWillBeMember<CSSRule> m_parentRule;
 };
 
 class InlineCSSStyleDeclaration final : public AbstractPropertySetCSSStyleDeclaration {
 public:
-    explicit InlineCSSStyleDeclaration(Element* parentElement)
-        : m_parentElement(parentElement)
-    {
-    }
+    explicit InlineCSSStyleDeclaration(Element* parentElement);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     MutableStylePropertySet& propertySet() const override;
 #if !ENABLE(OILPAN)
     void ref() override;
     void deref() override;
 #endif
     CSSStyleSheet* parentStyleSheet() const override;
-    Element* parentElement() const override { return m_parentElement; }
+    Element* parentElement() const override;
 
     void didMutate(MutationType) override;
 
     RawPtrWillBeMember<Element> m_parentElement;
 };
 
 } // namespace blink
 
 #endif