Rebuild layout tree in flat tree order.

third_party/WebKit/Source/core/html/HTMLSlotElement.cpp

 /*
  * Copyright (C) 2015 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 182 matching lines @@
 }
 
 void HTMLSlotElement::DetachLayoutTree(const AttachContext& context) {
   if (SupportsDistribution()) {
     for (auto& node : distributed_nodes_)
       node->LazyReattachIfAttached();
   }
   HTMLElement::DetachLayoutTree(context);
 }
 
+void HTMLSlotElement::RebuildDistributedChildrenLayoutTrees() {
+  if (!SupportsDistribution())
+    return;
+  Text* next_text_sibling = nullptr;
+  // This loop traverses the nodes from right to left for the same reason as the
+  // one described in ContainerNode::RebuildChildrenLayoutTrees().
+  for (auto it = distributed_nodes_.rbegin(); it != distributed_nodes_.rend();
+       ++it) {
+    RebuildLayoutTreeForChild(*it, next_text_sibling);
+  }
+}
+
 void HTMLSlotElement::AttributeChanged(
     const AttributeModificationParams& params) {
   if (params.name == nameAttr) {
     if (ShadowRoot* root = ContainingShadowRoot()) {
       if (root->IsV1() && params.old_value != params.new_value) {
         root->GetSlotAssignment().SlotRenamed(
             NormalizeSlotName(params.old_value), *this);
       }
     }
   }
@@ skipping 151 matching lines @@
 
 DEFINE_TRACE(HTMLSlotElement) {
   visitor->Trace(assigned_nodes_);
   visitor->Trace(distributed_nodes_);
   visitor->Trace(old_distributed_nodes_);
   visitor->Trace(distributed_indices_);
   HTMLElement::Trace(visitor);
 }
 
 }  // namespace blink