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

Source/core/dom/NodeRenderingTraversal.cpp

 /*
  * Copyright (C) 2012 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 31 matching lines @@
     }
 }
 
 void ParentDetails::didTraverseShadowRoot(const ShadowRoot* root)
 {
     m_resetStyleInheritance  = m_resetStyleInheritance || root->resetStyleInheritance();
 }
 
 ContainerNode* parent(const Node* node, ParentDetails* details)
 {
+    if (ShadowRoot* root = node->containingShadowRoot())
+        root->host()->ensureDistribution();
+
     ComposedShadowTreeWalker walker(node, ComposedShadowTreeWalker::CrossUpperBoundary, ComposedShadowTreeWalker::CanStartFromShadowBoundary);
     ContainerNode* found = toContainerNode(walker.traverseParent(walker.get(), details));
     return details->outOfComposition() ? 0 : found;
 }
 
 Node* nextSibling(const Node* node)
 {
     ComposedShadowTreeWalker walker(node);
     if (node->isBeforePseudoElement()) {
         walker.parent();
@@ skipping 54 matching lines @@
 Node* lastChildInScope(const Node* node)
 {
     ComposedShadowTreeWalker walker = ComposedShadowTreeWalker(node, ComposedShadowTreeWalker::DoNotCrossUpperBoundary);
     walker.lastChild();
     return walker.get();
 }
 
 }
 
 } // namespace