Fixed mouseenter/mouseleave event firing order.

Source/core/page/EventHandler.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 245 matching lines @@
     // absolutePoint - For wheel scrolls - the location, in absolute coordinates, where the event occured.
     bool scroll(ScrollDirection, ScrollGranularity, Node* startNode = nullptr, Node** stopNode = nullptr, float delta = 1.0f, IntPoint absolutePoint = IntPoint());
 
     TouchAction intersectTouchAction(const TouchAction, const TouchAction);
     TouchAction computeEffectiveTouchAction(const Node&);
 
     HitTestResult hitTestResultInFrame(LocalFrame*, const LayoutPoint&, HitTestRequest::HitTestRequestType hitType = HitTestRequest::ReadOnly | HitTestRequest::Active);
 
     void invalidateClick();
 
-    void updateMouseEventTargetNode(Node*, const PlatformMouseEvent&, bool fireMouseOverOut);
+    void updateMouseEventTargetNode(Node*, const PlatformMouseEvent&, bool);
+
+    /* Dispatches mouseover, mouseout, mouseenter and mouseleave events to appropriate nodes when the mouse pointer moves from one node to another. */
+    void sendMouseEventsForNodeTransition(Node*, Node*, const PlatformMouseEvent&);
 
     MouseEventWithHitTestResults prepareMouseEvent(const HitTestRequest&, const PlatformMouseEvent&);
 
     bool dispatchMouseEvent(const AtomicString& eventType, Node* target, int clickCount, const PlatformMouseEvent&, bool setUnder);
     bool dispatchDragEvent(const AtomicString& eventType, Node* target, const PlatformMouseEvent&, DataTransfer*);
 
     void clearDragDataTransfer();
 
     bool handleDrag(const MouseEventWithHitTestResults&, DragInitiator);
     bool tryStartDrag(const MouseEventWithHitTestResults&);
@@ skipping 120 matching lines @@
     bool m_longTapShouldInvokeContextMenu;
 
     Timer<EventHandler> m_activeIntervalTimer;
     double m_lastShowPressTimestamp;
     RefPtrWillBeMember<Element> m_lastDeferredTapElement;
 };
 
 } // namespace blink
 
 #endif // EventHandler_h