Skip updating nodeUnderMouse to clickTarget.

third_party/WebKit/Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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.
@@ skipping 1252 matching lines @@
 #endif
 
     bool swallowClickEvent = false;
     if (m_clickCount > 0 && !contextMenuEvent && mev.innerNode() && m_clickNode && mev.innerNode()->canParticipateInComposedTree() && m_clickNode->canParticipateInComposedTree()) {
         // Updates distribution because a 'mouseup' event listener can make the
         // tree dirty at dispatchMouseEvent() invocation above.
         // Unless distribution is updated, commonAncestor would hit ASSERT.
         // Both m_clickNode and mev.innerNode() don't need to be updated
         // because commonAncestor() will exit early if their documents are different.
         m_clickNode->updateDistribution();
-        if (Node* clickTargetNode = mev.innerNode()->commonAncestor(*m_clickNode, parentForClickEvent))
-            swallowClickEvent = !dispatchMouseEvent(EventTypeNames::click, clickTargetNode, m_clickCount, mouseEvent);
+        if (Node* clickTargetNode = mev.innerNode()->commonAncestor(
+            *m_clickNode, parentForClickEvent)) {
+
+            // Dispatch mouseup directly w/o calling updateMouseEventTargetNode
+            // because the mouseup dispatch above has already updated it
+            // correctly. Moreover, clickTargetNode is different from
+            // mev.innerNode at drag-release.
+            clickTargetNode->dispatchMouseEvent(mouseEvent,
+                EventTypeNames::click, m_clickCount);
+        }
     }
 
     if (m_resizeScrollableArea) {
         m_resizeScrollableArea->setInResizeMode(false);
         m_resizeScrollableArea = nullptr;
     }
 
     bool swallowMouseReleaseEvent = false;
     if (!swallowMouseUpEvent)
         swallowMouseReleaseEvent = handleMouseReleaseEvent(mev);
@@ skipping 2753 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink