[LayoutNG] Move legacy tree population logic

Move the logic in NGInlineNode that populates the legacy layout tree out
of NGInlineNode and into the new NGInlineNodeLegacy class.

Bug: 591099
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I7d228a1c9b1c28f301838336ecc1348eacb6e663
Reviewed-on: https://chromium-review.googlesource.com/898003Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533876}

third_party/WebKit/Source/core/layout/BUILD.gn

@@ -356,6 +356,8 @@ blink_core_sources("layout") {
     "ng/inline/ng_inline_node.h",
     "ng/inline/ng_inline_node_data.cc",
     "ng/inline/ng_inline_node_data.h",
+    "ng/inline/ng_inline_node_legacy.cc",
+    "ng/inline/ng_inline_node_legacy.h",
     "ng/inline/ng_line_box_fragment.cc",
     "ng/inline/ng_line_box_fragment.h",
     "ng/inline/ng_line_box_fragment_builder.cc",

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h

@@ -28,6 +28,7 @@ using NGInlineItemsBuilder =
 struct NGInlineNodeData;
 class NGLayoutResult;
 class NGOffsetMapping;
+class NGInlineNodeLegacy;
 
 // Represents an anonymous block box to be laid out, that contains consecutive
 // inline nodes and their descendants.
@@ -53,10 +54,6 @@ class CORE_EXPORT NGInlineNode : public NGLayoutInputNode {
   // opportunity, and max-content is when lines do not wrap at all.
   MinMaxSize ComputeMinMaxSize();
 
-  // Copy fragment data of all lines to LayoutBlockFlow.
-  void CopyFragmentDataToLayoutBox(const NGConstraintSpace&,
-                                   const NGLayoutResult&);
-
   // Instruct to re-compute |PrepareLayout| on the next layout.
   void InvalidatePrepareLayout();
 
@@ -69,7 +66,7 @@ class CORE_EXPORT NGInlineNode : public NGLayoutInputNode {
   const Vector<NGInlineItem>& Items(bool is_first_line = false) const;
   NGInlineItemRange Items(unsigned start_index, unsigned end_index);
 
-  void GetLayoutTextOffsets(Vector<unsigned, 32>*);
+  void GetLayoutTextOffsets(Vector<unsigned, 32>*) const;
 
   // Returns the DOM to text content offset mapping of this block. If it is not
   // computed before, compute and store it in NGInlineNodeData.
@@ -105,6 +102,7 @@ class CORE_EXPORT NGInlineNode : public NGLayoutInputNode {
   const NGInlineNodeData& EnsureData();
 
   friend class NGLineBreakerTest;
+  friend class NGInlineNodeLegacy;
 };
 
 inline void NGInlineNode::AssertOffset(unsigned index, unsigned offset) const {

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node_data.h

@@ -29,6 +29,7 @@ struct CORE_EXPORT NGInlineNodeData {
   }
 
   friend class NGInlineNode;
+  friend class NGInlineNodeLegacy;
   friend class NGInlineNodeForTest;
   friend class NGOffsetMappingTest;
 

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node_legacy.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NGInlineNodeLegacy_h
+#define NGInlineNodeLegacy_h
+
+#include "core/CoreExport.h"
+#include "core/layout/LayoutBlockFlow.h"
+#include "core/layout/line/LineInfo.h"
+#include "core/layout/line/RootInlineBox.h"
+
+namespace blink {
+
+class NGInlineNode;
+
+// Helper class actiong as a bridge between LayoutNG inline nodes and legacy
+// layout. Populates a LayoutBlockFlow with LayoutNG inline layout results.
+class CORE_EXPORT NGInlineNodeLegacy {
+ public:
+  NGInlineNodeLegacy(const NGInlineNode& node) : inline_node_(node) {}
+
+  // Copy fragment data of all lines to LayoutBlockFlow.
+  void CopyFragmentDataToLayoutBox(const NGConstraintSpace&,
+                                   const NGLayoutResult&);
+
+ private:
+  const NGInlineNode& inline_node_;
+};
+
+}  // namespace blink
+
+#endif  // NGInlineNodeLegacy_h

third_party/WebKit/Source/core/layout/ng/ng_block_node.cc

@@ -10,6 +10,7 @@
 #include "core/layout/LayoutTable.h"
 #include "core/layout/MinMaxSize.h"
 #include "core/layout/ng/inline/ng_inline_node.h"
+#include "core/layout/ng/inline/ng_inline_node_legacy.h"
 #include "core/layout/ng/inline/ng_physical_line_box_fragment.h"
 #include "core/layout/ng/layout_ng_block_flow.h"
 #include "core/layout/ng/legacy_layout_tree_walking.h"
@@ -186,10 +187,8 @@ scoped_refptr<NGLayoutResult> NGBlockNode::Layout(
     NGLayoutInputNode first_child = FirstChild();
     if (block_flow && first_child && first_child.IsInline()) {
       if (!RuntimeEnabledFeatures::LayoutNGPaintFragmentsEnabled()) {
-        // TODO(ikilpatrick): Move line-box creation logic from
-        // NGInlineNode::CopyFragmentDataToLayoutBox to NGBlockNode.
-        NGInlineNode node = ToNGInlineNode(first_child);
-        node.CopyFragmentDataToLayoutBox(constraint_space, *layout_result);
+        NGInlineNodeLegacy(ToNGInlineNode(first_child))
+            .CopyFragmentDataToLayoutBox(constraint_space, *layout_result);
       } else {
         CopyFragmentDataToLayoutBoxForInlineChildren(
             ToNGPhysicalBoxFragment(*layout_result->PhysicalFragment()));