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

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 52 matching lines @@
 
     bool canProcessDrag() const;
 
     virtual bool willRespondToMouseClickEvents() OVERRIDE;
 
     virtual bool isPlugInImageElement() const { return false; }
 
 protected:
     HTMLPlugInElement(const QualifiedName& tagName, Document*);
 
-    virtual void detach();
+    virtual void detach(const AttachContext& = AttachContext()) OVERRIDE;
     virtual bool isPresentationAttribute(const QualifiedName&) const OVERRIDE;
     virtual void collectStyleForPresentationAttribute(const QualifiedName&, const AtomicString&, MutableStylePropertySet*) OVERRIDE;
 
     virtual bool useFallbackContent() const { return false; }
 
     virtual bool dispatchBeforeLoadEvent(const String& sourceURL) OVERRIDE;
 
 private:
     virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
 
@@ skipping 24 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isPluginElement());
     return static_cast<const HTMLPlugInElement*>(node);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toHTMLPlugInElement(const HTMLPlugInElement*);
 
 } // namespace WebCore
 
 #endif // HTMLPlugInElement_h