InlinedVisitor: Migrate html to use inlined tracing

Source/core/html/HTMLPlugInElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 27 matching lines @@
 class Widget;
 
 enum PreferPlugInsForImagesOption {
     ShouldPreferPlugInsForImages,
     ShouldNotPreferPlugInsForImages
 };
 
 class HTMLPlugInElement : public HTMLFrameOwnerElement {
 public:
     virtual ~HTMLPlugInElement();
-    virtual void trace(Visitor*) override;
+    DECLARE_VIRTUAL_TRACE();
 #if ENABLE(OILPAN)
     virtual void disconnectContentFrame() override;
     void shouldDisposePlugin();
 #endif
 
     void resetInstance();
 
     // Returns the existing plugin widget, if there is one.
     Widget* existingPluginWidget() const;
 
@@ skipping 108 matching lines @@
 inline bool isHTMLPlugInElement(const HTMLElement& element)
 {
     return element.isPluginElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLPlugInElement);
 
 } // namespace blink
 
 #endif // HTMLPlugInElement_h