[Oilpan] Prepare full definition of classes before using Member

third_party/WebKit/Source/web/WebPluginLoadObserver.h

 /*
  * Copyright (C) 2009 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
 
 #if !ENABLE(OILPAN)
     void clearPluginContainer() { m_pluginContainer = nullptr; }
 #endif
     void didFinishLoading();
     void didFailLoading(const WebURLError&);
 
     DECLARE_TRACE();
 
 private:
-    WebPluginLoadObserver(WebPluginContainerImpl* pluginContainer, const WebURL& notifyURL, void* notifyData)
-        : m_pluginContainer(pluginContainer)
-        , m_notifyURL(notifyURL)
-        , m_notifyData(notifyData)
-    {
-    }
+    WebPluginLoadObserver(WebPluginContainerImpl*, const WebURL&, void*);
 
     RawPtrWillBeWeakMember<WebPluginContainerImpl> m_pluginContainer;
     WebURL m_notifyURL;
     void* m_notifyData;
 };
 
 } // namespace blink
 
 #endif