Make all setNeedsReattachLayoutTree happen from updateStyle.

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

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index 98b470d9c02d0c16392046c30aaf2d6c6344114c..ec0b25ec392d2827a53f4c1692c021a134f47735 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -725,6 +725,8 @@ void Node::markAncestorsWithChildNeedsReattachLayoutTree() {
 }
 
 void Node::setNeedsReattachLayoutTree() {
+  DCHECK(document().inStyleRecalc() &&

[esprehn, 2017/03/21 20:59:56]

Can we use two DCHECKs so it's clear which side failed?

[rune, 2017/03/21 22:25:15]

Done.

+         !document().childNeedsDistributionRecalc());
   setFlag(NeedsReattachLayoutTree);
   markAncestorsWithChildNeedsReattachLayoutTree();
 }
@@ -932,7 +934,6 @@ void Node::detachLayoutTree(const AttachContext& context) {
     layoutObject()->destroyAndCleanupAnonymousWrappers();
   setLayoutObject(nullptr);
   setStyleChange(NeedsReattachStyleChange);
-  setFlag(NeedsReattachLayoutTree);
   clearChildNeedsStyleInvalidation();
 }