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

Source/core/dom/NodeRenderingTraversal.cpp

Index: Source/core/dom/NodeRenderingTraversal.cpp
diff --git a/Source/core/dom/NodeRenderingTraversal.cpp b/Source/core/dom/NodeRenderingTraversal.cpp
index fa67f825e242ba68373c4cbb2d617e8105731054..a04d7633ef7dc80f43faf622edbcf7f925e2d8a9 100644
--- a/Source/core/dom/NodeRenderingTraversal.cpp
+++ b/Source/core/dom/NodeRenderingTraversal.cpp
@@ -49,6 +49,9 @@ void ParentDetails::didTraverseShadowRoot(const ShadowRoot* root)
 
 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;