[Oilpan] Prepare full definition of classes before using Member

third_party/WebKit/Source/modules/storage/StorageEvent.h

 /*
  * Copyright (C) 2008, 2009 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 29 matching lines @@
 public:
     static PassRefPtrWillBeRawPtr<StorageEvent> create();
     static PassRefPtrWillBeRawPtr<StorageEvent> create(const AtomicString& type, const String& key, const String& oldValue, const String& newValue, const String& url, Storage* storageArea);
     static PassRefPtrWillBeRawPtr<StorageEvent> create(const AtomicString&, const StorageEventInit&);
     ~StorageEvent() override;
 
     const String& key() const { return m_key; }
     const String& oldValue() const { return m_oldValue; }
     const String& newValue() const { return m_newValue; }
     const String& url() const { return m_url; }
-    Storage* storageArea() const { return m_storageArea.get(); }
+    Storage* storageArea() const;
 
     void initStorageEvent(const AtomicString& type, bool canBubble, bool cancelable, const String& key, const String& oldValue, const String& newValue, const String& url, Storage* storageArea);
 
     // Needed once we support init<blank>EventNS
     // void initStorageEventNS(in DOMString namespaceURI, in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in DOMString keyArg, in DOMString oldValueArg, in DOMString newValueArg, in DOMString urlArg, Storage storageAreaArg);
 
     const AtomicString& interfaceName() const override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     StorageEvent();
     StorageEvent(const AtomicString& type, const String& key, const String& oldValue, const String& newValue, const String& url, Storage* storageArea);
     StorageEvent(const AtomicString&, const StorageEventInit&);
 
     String m_key;
     String m_oldValue;
     String m_newValue;
     String m_url;
     PersistentWillBeMember<Storage> m_storageArea;
 };
 
 } // namespace blink
 
 #endif // StorageEvent_h