Do not invoke or clear hover effects on node deletion when cursor is invisible

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 3096 matching lines @@
 }
 
 void Document::hoveredNodeDetached(Node* node)
 {
     if (!m_hoverNode || (node != m_hoverNode && (!m_hoverNode->isTextNode() || node != m_hoverNode->parentNode())))
         return;
 
     m_hoverNode = node->parentNode();
     while (m_hoverNode && !m_hoverNode->renderer())
         m_hoverNode = m_hoverNode->parentNode();
+
+    // If the mouse cursor is not visible, do not clear existing
+    // hover effects on the ancestors of |node| and do not invoke
+    // new hover effects on any other element.
+    if (!page()->isCursorVisible())
+        return;
+
     if (frame())
         frame()->eventHandler()->scheduleHoverStateUpdate();
 }
 
 void Document::activeChainNodeDetached(Node* node)
 {
     if (!m_activeElement || (node != m_activeElement && (!m_activeElement->isTextNode() || node != m_activeElement->parentNode())))
         return;
 
     m_activeElement = node->parentElement();
@@ skipping 2487 matching lines @@
         return;
 
     Vector<RefPtr<Element> > associatedFormControls;
     copyToVector(m_associatedFormControls, associatedFormControls);
 
     frame()->page()->chrome().client()->didAssociateFormControls(associatedFormControls);
     m_associatedFormControls.clear();
 }
 
 } // namespace WebCore