Call Element::rebuildLayoutTree from Document::updateStyle directly

third_party/WebKit/Source/core/dom/Text.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 377 matching lines @@
         .createLayoutObject();
   CharacterData::attachLayoutTree(reattachContext);
 }
 
 void Text::recalcTextStyle(StyleRecalcChange change, Text* nextTextSibling) {
   if (LayoutTextItem layoutItem = LayoutTextItem(this->layoutObject())) {
     if (change != NoChange || needsStyleRecalc())
       layoutItem.setStyle(document().ensureStyleResolver().styleForText(this));
     if (needsStyleRecalc())
       layoutItem.setText(dataImpl());
-    clearNeedsStyleRecalc();
   } else if (needsStyleRecalc() || needsWhitespaceLayoutObject()) {
-    rebuildTextLayoutTree(nextTextSibling);
+    setNeedsReattachLayoutTree();
   }
+  clearNeedsStyleRecalc();
 }
 
-void Text::rebuildTextLayoutTree(Text* nextTextSibling) {

[nainar, 2016/11/03 00:17:10]

If bugs finishes his patch before this needs to land - I will rebase to not call
nextTextSibling() here and instead use the value from the HashMap

+void Text::rebuildTextLayoutTree() {
+  DCHECK(!needsStyleRecalc());
+  DCHECK(!childNeedsStyleRecalc());
+  DCHECK(needsReattachLayoutTree());
+
   reattachLayoutTree();
-  if (layoutObject())
-    reattachWhitespaceSiblingsIfNeeded(nextTextSibling);
+  if (layoutObject()) {
+    // TODO(bugsnash): This is a performance regression - bugsnash is working on
+    // alleviating this regression
+    reattachWhitespaceSiblingsIfNeeded(nextTextSibling());
+  }
   clearNeedsReattachLayoutTree();
 }
 
 // If a whitespace node had no layoutObject and goes through a recalcStyle it
 // may need to create one if the parent style now has white-space: pre.
 bool Text::needsWhitespaceLayoutObject() {
   DCHECK(!layoutObject());
   if (const ComputedStyle* style = parentComputedStyle())
     return style->preserveNewline();
   return false;
@@ skipping 32 matching lines @@
 
 Text* Text::cloneWithData(const String& data) {
   return create(document(), data);
 }
 
 DEFINE_TRACE(Text) {
   CharacterData::trace(visitor);
 }
 
 }  // namespace blink