Make sure to lazyReattach a distributed node if it is already attached

third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/shadow/SlotAssignment.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/shadow/ElementShadow.h"
@@ skipping 98 matching lines @@
 
 static void detachNotAssignedNode(Node& node)
 {
     if (node.layoutObject())
         node.lazyReattachIfAttached();
 }
 
 void SlotAssignment::resolveAssignment()
 {
     for (Member<HTMLSlotElement> slot : slots())
-        slot->clearDistribution();
+        slot->saveAndClearDistribution();
 
     for (Node& child : NodeTraversal::childrenOf(m_owner->host())) {
         if (!child.isSlotable()) {
             detachNotAssignedNode(child);
             continue;
         }
         HTMLSlotElement* slot = findSlotByName(child.slotName());
         if (slot)
             slot->appendAssignedNode(child);
         else
             detachNotAssignedNode(child);
     }
 }
 
 void SlotAssignment::resolveDistribution()
 {
     resolveAssignment();
     const HeapVector<Member<HTMLSlotElement>>& slots = this->slots();
 
     for (auto slot : slots)
         slot->resolveDistributedNodes();
 
     // Update each slot's distribution in reverse tree order so that a child slot is visited before its parent slot.
-    for (auto slot = slots.rbegin(); slot != slots.rend(); ++slot)
+    for (auto slot = slots.rbegin(); slot != slots.rend(); ++slot) {
         (*slot)->updateDistributedNodesWithFallback();
+        (*slot)->lazyReattachDistributedNodesIfNeeded();
+    }
 }
 
 const HeapVector<Member<HTMLSlotElement>>& SlotAssignment::slots()
 {
     if (m_needsCollectSlots)
         collectSlots();
     return m_slots;
 }
 
 HTMLSlotElement* SlotAssignment::findSlot(const Node& node)
@@ skipping 20 matching lines @@
 }
 
 DEFINE_TRACE(SlotAssignment)
 {
     visitor->trace(m_slots);
     visitor->trace(m_slotMap);
     visitor->trace(m_owner);
 }
 
 } // namespace blink