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 d5e59f90244c194809224a45f0f64f44e4fc4c27..b0406d907daf3ac8d3ad678a87cd8c8d1fa6b63a 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -606,7 +606,44 @@ 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);
+  DCHECK(!node_layout_data->GetNonAttachedStyle());
+  node_layout_data = new NodeLayoutData(layout_object, nullptr);
+  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_;
+
+  if (!node_layout_data->IsSharedEmptyData()) {
+    if (non_attached_style) {
+      node_layout_data->SetNonAttachedStyle(non_attached_style);
+    } else {
+      if (node_layout_data->GetLayoutObject()) {
+        node_layout_data->SetNonAttachedStyle(nullptr);
+      } else {
+        if (HasRareData()) {
+          data_.rare_data_->SetNodeLayoutData(
+              &NodeLayoutData::SharedEmptyData());
+        } else {
+          data_.node_layout_data_ = &NodeLayoutData::SharedEmptyData();

[rune, 2017/04/26 08:47:28]

Won't this leak the previously set node_layout_data_?

Could we just keep the node_layout_data_ like we do for rare data?

[nainar, 2017/04/27 01:50:06]

Yup, I see what you mean. I have reverted the CL back to the patch where I had
your LGTM last. Sorry about that I thought it was an lgtm with the suggested
change. 

I will take another stab at this when I try to unify the two ComputedStyles. 

+        }
+      }
+    }
+    return;
+  }
+
+  if (!non_attached_style)
+    return;
+
+  // Swap the NodeLayoutData to point to a new NodeLayoutData instead of the
+  // static SharedEmptyData instance.
+  DCHECK(!node_layout_data->GetLayoutObject());
+  node_layout_data = new NodeLayoutData(nullptr, non_attached_style);
   if (HasRareData())
     data_.rare_data_->SetNodeLayoutData(node_layout_data);
   else