Call Element::rebuildLayoutTree from Document::updateStyle directly

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

 /*
  * 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, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
@@ skipping 895 matching lines @@
 }
 
 void Node::detachLayoutTree(const AttachContext& context) {
   DCHECK(document().lifecycle().stateAllowsDetach());
   DocumentLifecycle::DetachScope willDetach(document().lifecycle());
 
   if (layoutObject())
     layoutObject()->destroyAndCleanupAnonymousWrappers();
   setLayoutObject(nullptr);
   setStyleChange(NeedsReattachStyleChange);
+  setLocalNeedsReattachLayoutTree();

[nainar, 2016/12/07 14:48:21]

make sure that we are setting the NeedsReattachLayoutTree flag on each node that
we set NeedsReattachStyleChange information on. 

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

this function is difficult to understand at first glance. shouldn't this be
calling setNeedsReattachLayoutTree() so that the ancestors are marked too?
alternatively if you're not setting it cause you can guarantee it will be
immediately attached after this then setting the NeedsReattachLayoutTree flag
shouldn't be necessary

[nainar, 2016/12/07 23:49:10]

As per discussion with esprehn@, we want to set the NeedsReattachLayoutTree flag
only on the node itself and check that wherever we set the
NeedsReattachStyleChange flag to make sure that we attach all nodes that need it
and then clear the bits correctly.

The line directly above also doesn't call Node::setNeedsStyleRecalc() with the
NeedsReattachStyleChange flag (which would amongst other things set the
childNeedsStyleRecalc flag on the ancestors) but instead only sets the flag on
the node itself.

[Bugs Nash, 2016/12/08 00:27:59]

If this is similar to the above call then I would recommend naming it similarly.
It's not clear what 'local' means here.

[nainar, 2016/12/08 00:45:48]

Yup that makes sense calling setFlag(NeedsReattachLayoutTree) directly here
instead of that. Made the change locally. 

   clearChildNeedsStyleInvalidation();
 }
 
 void Node::reattachWhitespaceSiblingsIfNeeded(Text* start) {
   ScriptForbiddenScope forbidScriptDuringRawIteration;
   for (Node* sibling = start; sibling; sibling = sibling->nextSibling()) {
     if (sibling->isTextNode() && toText(sibling)->containsOnlyWhitespace()) {
       bool hadLayoutObject = !!sibling->layoutObject();
       toText(sibling)->reattachLayoutTreeIfNeeded();
       // If sibling's layout object status didn't change we don't need to
@@ skipping 1615 matching lines @@
   if (node) {
     std::stringstream stream;
     node->printNodePathTo(stream);
     LOG(INFO) << stream.str();
   } else {
     LOG(INFO) << "Cannot showNodePath for <null>";
   }
 }
 
 #endif