Store nonAttachedStyle on NodeLayoutData instead of on HashMap in Document.

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 a61464b7c7b714a55b57fa53ef6c8f894772ec11..9fc6d97fedbc98c82cf6fb686a7880e6418b4b96 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -605,7 +605,33 @@ void Node::SetLayoutObject(LayoutObject* layout_object) {
 
   // Swap the NodeLayoutData to point to a new NodeLayoutData instead of the
   // static SharedEmptyData instance.
-  node_layout_data = new NodeLayoutData(layout_object);
+  node_layout_data = new NodeLayoutData(
+      layout_object, node_layout_data->GetNonAttachedStyle());

[nainar, 2017/04/18 03:48:12]

at this stage the GetNonAttachedStyle call should return a nullptr. Assign
nullptr here instead?

[esprehn, 2017/04/18 21:31:10]

Yeah can we make this a DCHECK and remove the constructor argument instead? Just
initialize directly to nullptr. I don't think saving the one assignment is worth
it in general.

[nainar, 2017/04/19 01:38:34]

Done.

+  if (HasRareData())
+    data_.rare_data_->SetNodeLayoutData(node_layout_data);
+  else
+    data_.node_layout_data_ = node_layout_data;
+}
+
+void Node::SetNonAttachedStyle(RefPtr<ComputedStyle> non_attached_style) {
+  NodeLayoutData* node_layout_data = HasRareData()
+                                         ? data_.rare_data_->GetNodeLayoutData()
+                                         : data_.node_layout_data_;
+
+  // Already pointing to a non empty NodeLayoutData so just set the pointer to
+  // the new LayoutObject.
+  if (!node_layout_data->IsSharedEmptyData()) {
+    node_layout_data->SetNonAttachedStyle(non_attached_style);
+    return;
+  }
+
+  if (!non_attached_style)
+    return;
+
+  // Swap the NodeLayoutData to point to a new NodeLayoutData instead of the
+  // static SharedEmptyData instance.
+  node_layout_data = new NodeLayoutData(node_layout_data->GetLayoutObject(),

[nainar, 2017/04/18 03:48:12]

at this stage the GetLayoutObject call should return a nullptr. Assign nullptr
here instead?

[nainar, 2017/04/19 01:38:34]

Done. 

+                                        non_attached_style);
   if (HasRareData())
     data_.rare_data_->SetNodeLayoutData(node_layout_data);
   else