Call Element::rebuildLayoutTree from Document::updateStyle directly

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

Index: third_party/WebKit/Source/core/dom/ContainerNode.h
diff --git a/third_party/WebKit/Source/core/dom/ContainerNode.h b/third_party/WebKit/Source/core/dom/ContainerNode.h
index 385aa49a93e021f5d03f8c5f15951f939dc62990..a2093438fbe5c70b75e1bb3ad3aa627b0bd06541 100644
--- a/third_party/WebKit/Source/core/dom/ContainerNode.h
+++ b/third_party/WebKit/Source/core/dom/ContainerNode.h
@@ -240,6 +240,7 @@ class CORE_EXPORT ContainerNode : public Node {
                                    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(); }