Implement 'mouseenter' and 'mouseleave' from DOM Level 3 Events.

Source/core/dom/Document.h

 /*
  * 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, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 236 matching lines @@
     DEFINE_ATTRIBUTE_EVENT_LISTENER(drop);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(dragstart);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(drag);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(dragend);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(input);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(invalid);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(keydown);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(keypress);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(keyup);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mousedown);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(mouseenter);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(mouseleave);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mousemove);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mouseout);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mouseover);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mouseup);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(mousewheel);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(scroll);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(select);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(submit);
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(blur);
@@ skipping 385 matching lines @@
     void setHoverNode(PassRefPtr<Node>);
     Node* hoverNode() const { return m_hoverNode.get(); }
 
     void setActiveElement(PassRefPtr<Element>);
     Element* activeElement() const { return m_activeElement.get(); }
 
     void removeFocusedNodeOfSubtree(Node*, bool amongChildrenOnly = false);
     void hoveredNodeDetached(Node*);
     void activeChainNodeDetached(Node*);
 
-    void updateHoverActiveState(const HitTestRequest&, Element*);
+    void updateHoverActiveState(const HitTestRequest&, Element*, const PlatformMouseEvent* = 0);
 
     // Updates for :target (CSS3 selector).
     void setCSSTarget(Element*);
     Element* cssTarget() const { return m_cssTarget; }
     
     void scheduleForcedStyleRecalc();
     void scheduleStyleRecalc();
     void unscheduleStyleRecalc();
     bool hasPendingStyleRecalc() const;
     bool hasPendingForcedStyleRecalc() const;
@@ skipping 769 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == documentInternal();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h