Call Element::rebuildLayoutTree from Document::updateStyle directly

third_party/WebKit/Source/core/dom/ContainerNode.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011, 2013 Apple Inc. All
  * rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 222 matching lines @@
   enum SiblingCheckType {
     FinishedParsingChildren,
     SiblingElementInserted,
     SiblingElementRemoved
   };
   void checkForSiblingStyleChanges(SiblingCheckType,
                                    Element* changedElement,
                                    Node* nodeBeforeChange,
                                    Node* nodeAfterChange);
   void recalcDescendantStyles(StyleRecalcChange);
+  void rebuildDescendantLayoutTrees();

[Bugs Nash, 2016/12/07 23:21:44]

This name is strange (as I commented in the design doc). I think you mean
reattach descendent nodes or rebuild children trees. I recommend
rebuildChildrenLayoutTrees.

[nainar, 2016/12/07 23:49:09]

I'm good with renaming it to rebuildChildrenLayoutTrees() -> done so locally.

 
   bool childrenSupportStyleSharing() const { return !hasRestyleFlags(); }
 
   // -----------------------------------------------------------------------------
   // Notification of document structure changes (see core/dom/Node.h for more
   // notification methods)
 
   enum ChildrenChangeType {
     ElementInserted,
     NonElementInserted,
@@ skipping 206 matching lines @@
 
 inline void getChildNodes(ContainerNode& node, NodeVector& nodes) {
   DCHECK(!nodes.size());
   for (Node* child = node.firstChild(); child; child = child->nextSibling())
     nodes.append(child);
 }
 
 }  // namespace blink
 
 #endif  // ContainerNode_h