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

Source/core/dom/shadow/ShadowRoot.h

 /*
  * Copyright (C) 2011 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 60 matching lines @@
     void setInnerHTML(const String&, ExceptionCode&);
 
     Element* activeElement() const;
 
     ShadowRoot* youngerShadowRoot() const { return prev(); }
     ShadowRoot* olderShadowRoot() const { return next(); }
 
     bool isYoungest() const { return !youngerShadowRoot(); }
     bool isOldest() const { return !olderShadowRoot(); }
 
-    virtual void attach();
+    virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
 
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
 
     virtual void registerScopedHTMLStyleChild() OVERRIDE;
     virtual void unregisterScopedHTMLStyleChild() OVERRIDE;
 
     ScopeContentDistribution* scopeDistribution() { return m_scopeDistribution.get(); }
     const ScopeContentDistribution* scopeDistribution() const { return m_scopeDistribution.get(); }
     ScopeContentDistribution* ensureScopeDistribution();
@@ skipping 43 matching lines @@
 }
 
 inline ShadowRoot* toShadowRoot(Node* node)
 {
     return const_cast<ShadowRoot*>(toShadowRoot(static_cast<const Node*>(node)));
 }
 
 } // namespace
 
 #endif