Move LayoutObject to satellite NodeLayoutData that hangs from a Node.

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

Index: third_party/WebKit/Source/core/dom/NodeRareData.h
diff --git a/third_party/WebKit/Source/core/dom/NodeRareData.h b/third_party/WebKit/Source/core/dom/NodeRareData.h
index f33fbe6f6d41bc3223eb461cb410ea55f6eb2453..6cb30d2e24d99bd38884758ad47dceaabe995211 100644
--- a/third_party/WebKit/Source/core/dom/NodeRareData.h
+++ b/third_party/WebKit/Source/core/dom/NodeRareData.h
@@ -98,8 +98,8 @@ class NodeRareData : public GarbageCollectedFinalized<NodeRareData>,
   WTF_MAKE_NONCOPYABLE(NodeRareData);
 
  public:
-  static NodeRareData* Create(LayoutObject* layout_object) {
-    return new NodeRareData(layout_object);
+  static NodeRareData* Create(NodeLayoutData* node_layout_data) {
+    return new NodeRareData(node_layout_data);
   }
 
   void ClearNodeLists() { node_lists_.Clear(); }
@@ -163,8 +163,8 @@ class NodeRareData : public GarbageCollectedFinalized<NodeRareData>,
   DECLARE_TRACE_WRAPPERS_AFTER_DISPATCH();
 
  protected:
-  explicit NodeRareData(LayoutObject* layout_object)
-      : NodeRareDataBase(layout_object),
+  explicit NodeRareData(NodeLayoutData* node_layout_data)

[esprehn, 2017/04/13 18:41:08]

Can we add a DCHECK_NE(nullptr, node_layout_data) in the body here since it
should never be null?

[nainar, 2017/04/13 20:21:03]

Done. 

+      : NodeRareDataBase(node_layout_data),
         connected_frame_count_(0),
         element_flags_(0),
         restyle_flags_(0),