Element::recalcStyle() overly reattach()-es InsertionPoints.

Source/core/dom/EventPathWalker.cpp

 /*
  * Copyright (C) 2013 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 35 matching lines @@
     EventPathWalker walker(node);
     walker.moveToParent();
     return walker.node();
 }
 
 void EventPathWalker::moveToParent()
 {
     ASSERT(m_node);
     ASSERT(m_distributedNode);
     if (ElementShadow* shadow = shadowOfParent(m_node)) {
-        ContentDistributor::ensureDistribution(shadow->youngestShadowRoot());
+        shadow->host()->ensureDistribution();
         if (InsertionPoint* insertionPoint = shadow->distributor().findInsertionPointFor(m_distributedNode)) {
             m_node = insertionPoint;
             m_isVisitingInsertionPointInReprojection = true;
             return;
         }
     }
     if (!m_node->isShadowRoot()) {
         m_node = m_node->parentNode();
         if (!(m_node && m_node->isShadowRoot() && ScopeContentDistribution::assignedTo(toShadowRoot(m_node))))
             m_distributedNode = m_node;
         m_isVisitingInsertionPointInReprojection = false;
         return;
     }
 
     const ShadowRoot* shadowRoot = toShadowRoot(m_node);
     if (InsertionPoint* insertionPoint = ScopeContentDistribution::assignedTo(shadowRoot)) {
         m_node = insertionPoint;
         m_isVisitingInsertionPointInReprojection = true;
         return;
     }
     m_node = shadowRoot->host();
     m_distributedNode = m_node;
     m_isVisitingInsertionPointInReprojection = false;
 }
 
 } // namespace