:hover style not applied on hover if its display property is different from original style's

Source/core/html/HTMLPlugInImageElement.h

 /*
  * Copyright (C) 2008, 2009, 2011, 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 71 matching lines @@
     HTMLPlugInImageElement(const QualifiedName& tagName, Document*, bool createdByParser, PreferPlugInsForImagesOption);
 
     bool isImageType();
 
     OwnPtr<HTMLImageLoader> m_imageLoader;
     String m_serviceType;
     String m_url;
     KURL m_loadedUrl;
     
     static void updateWidgetCallback(Node*);
-    virtual void attach();
-    virtual void detach();
+    virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
+    virtual void detach(const AttachContext& = AttachContext()) OVERRIDE;
 
     bool allowedToLoadFrameURL(const String& url);
     bool wouldLoadAsNetscapePlugin(const String& url, const String& serviceType);
 
     virtual void didMoveToNewDocument(Document* oldDocument) OVERRIDE;
 
 private:
     virtual RenderObject* createRenderer(RenderArena*, RenderStyle*);
     virtual void willRecalcStyle(StyleChange) OVERRIDE FINAL;
 
@@ skipping 27 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(plugInElement->isPlugInImageElement());
     return static_cast<const HTMLPlugInImageElement*>(plugInElement);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toHTMLPlugInImageElement(const HTMLPlugInImageElement*);
 
 } // namespace WebCore
 
 #endif // HTMLPlugInImageElement_h