[FragmentItem] Make NGFragmentItem RefCounted

This patch makes |NGFragmentItem| RefCounted.

Bug: 982194
Change-Id: I04340c91b52ad4e274c70f3c99f8e4a3e32f4ad3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135672
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756542}

third_party/blink/renderer/core/layout/ng/inline/ng_fragment_item.h

@@ -5,6 +5,7 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_INLINE_NG_FRAGMENT_ITEM_H_
 #define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_INLINE_NG_FRAGMENT_ITEM_H_
 
+#include "base/memory/scoped_refptr.h"
 #include "third_party/blink/renderer/core/core_export.h"
 #include "third_party/blink/renderer/core/layout/geometry/logical_offset.h"
 #include "third_party/blink/renderer/core/layout/layout_object.h"
@@ -14,6 +15,7 @@
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_text_offset.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_ink_overflow.h"
 #include "third_party/blink/renderer/platform/graphics/paint/display_item_client.h"
+#include "third_party/blink/renderer/platform/wtf/ref_counted.h"
 
 namespace blink {
 
@@ -26,7 +28,8 @@ struct NGTextFragmentPaintInfo;
 //
 // This class consumes less memory than a full fragment, and can be stored in a
 // flat list (NGFragmentItems) for easier and faster traversal.
-class CORE_EXPORT NGFragmentItem : public DisplayItemClient {
+class CORE_EXPORT NGFragmentItem : public RefCounted<NGFragmentItem>,
+                                   public DisplayItemClient {
  public:
   // Represents regular text that exists in the DOM.
   struct TextItem {

third_party/blink/renderer/core/layout/ng/inline/ng_fragment_items.cc

@@ -23,7 +23,7 @@ NGFragmentItems::NGFragmentItems(NGFragmentItemsBuilder* builder)
       first_line_text_content_(std::move(builder->first_line_text_content_)) {}
 
 void NGFragmentItems::AssociateWithLayoutObject() const {
-  const Vector<std::unique_ptr<NGFragmentItem>>* items = &items_;
+  const Vector<scoped_refptr<NGFragmentItem>>* items = &items_;
   DCHECK(std::all_of(items->begin(), items->end(), [](const auto& item) {
     return !item->DeltaToNextForSameLayoutObject();
   }));
@@ -62,7 +62,7 @@ void NGFragmentItems::ClearAssociatedFragments() const {
   if (items_.size() <= 1)
     return;
   LayoutObject* last_object = nullptr;
-  for (const auto& item : base::span<const std::unique_ptr<NGFragmentItem>>(
+  for (const auto& item : base::span<const scoped_refptr<NGFragmentItem>>(
            items_.begin() + 1, items_.end())) {
     if (!ShouldAssociateWithLayoutObject(*item)) {
       // These items are not associated and that no need to clear.

third_party/blink/renderer/core/layout/ng/inline/ng_fragment_items.h

@@ -20,9 +20,7 @@ class CORE_EXPORT NGFragmentItems {
  public:
   NGFragmentItems(NGFragmentItemsBuilder* builder);
 
-  const Vector<std::unique_ptr<NGFragmentItem>>& Items() const {
-    return items_;
-  }
+  const Vector<scoped_refptr<NGFragmentItem>>& Items() const { return items_; }
 
   const String& Text(bool first_line) const {
     return UNLIKELY(first_line) ? first_line_text_content_ : text_content_;
@@ -38,7 +36,7 @@ class CORE_EXPORT NGFragmentItems {
 
  private:
   // TODO(kojii): inline capacity TBD.
-  Vector<std::unique_ptr<NGFragmentItem>> items_;
+  Vector<scoped_refptr<NGFragmentItem>> items_;
   String text_content_;
   String first_line_text_content_;
 };

third_party/blink/renderer/core/layout/ng/inline/ng_fragment_items_builder.cc

@@ -50,7 +50,8 @@ void NGFragmentItemsBuilder::AddLine(const NGPhysicalLineBoxFragment& line,
 
   // All children are added. Create an item for the start of the line.
   wtf_size_t item_count = items_.size() - line_start_index;
-  items_[line_start_index] = std::make_unique<NGFragmentItem>(line, item_count);
+  items_[line_start_index] =
+      base::MakeRefCounted<NGFragmentItem>(line, item_count);
   // TODO(kojii): We probably need an end marker too for the reverse-order
   // traversals.
 
@@ -70,7 +71,7 @@ void NGFragmentItemsBuilder::AddItems(Child* child_begin, Child* child_end) {
   for (Child* child_iter = child_begin; child_iter != child_end;) {
     Child& child = *child_iter;
     if (const NGPhysicalTextFragment* text = child.fragment.get()) {
-      items_.push_back(std::make_unique<NGFragmentItem>(*text));
+      items_.push_back(base::MakeRefCounted<NGFragmentItem>(*text));
       offsets_.push_back(child.rect.offset);
       ++child_iter;
       continue;
@@ -78,14 +79,15 @@ void NGFragmentItemsBuilder::AddItems(Child* child_begin, Child* child_end) {
 
     if (child.layout_result || child.inline_item) {
       // Create an item if this box has no inline children.
-      std::unique_ptr<NGFragmentItem> item;
+      scoped_refptr<NGFragmentItem> item;
       if (child.layout_result) {
         const NGPhysicalBoxFragment& box =
             To<NGPhysicalBoxFragment>(child.layout_result->PhysicalFragment());
-        item = std::make_unique<NGFragmentItem>(box, child.ResolvedDirection());
+        item = base::MakeRefCounted<NGFragmentItem>(box,
+                                                    child.ResolvedDirection());
       } else {
         DCHECK(child.inline_item);
-        item = std::make_unique<NGFragmentItem>(
+        item = base::MakeRefCounted<NGFragmentItem>(
             *child.inline_item,
             ToPhysicalSize(child.rect.size,
                            child.inline_item->Style()->GetWritingMode()));
@@ -140,12 +142,12 @@ void NGFragmentItemsBuilder::AddListMarker(
   // Resolved direction matters only for inline items, and outside list markers
   // are not inline.
   const TextDirection resolved_direction = TextDirection::kLtr;
-  items_.push_back(
-      std::make_unique<NGFragmentItem>(marker_fragment, resolved_direction));
+  items_.push_back(base::MakeRefCounted<NGFragmentItem>(marker_fragment,
+                                                        resolved_direction));
   offsets_.push_back(offset);
 }
 
-const Vector<std::unique_ptr<NGFragmentItem>>& NGFragmentItemsBuilder::Items(
+const Vector<scoped_refptr<NGFragmentItem>>& NGFragmentItemsBuilder::Items(
     WritingMode writing_mode,
     TextDirection direction,
     const PhysicalSize& outer_size) {
@@ -166,7 +168,7 @@ void NGFragmentItemsBuilder::ConvertToPhysical(WritingMode writing_mode,
   // convert their logical offsets.
   const WritingMode line_writing_mode = ToLineWritingMode(writing_mode);
 
-  std::unique_ptr<NGFragmentItem>* item_iter = items_.begin();
+  scoped_refptr<NGFragmentItem>* item_iter = items_.begin();
   const LogicalOffset* offset = offsets_.begin();
   for (; item_iter != items_.end(); ++item_iter, ++offset) {
     DCHECK_NE(offset, offsets_.end());
@@ -205,7 +207,7 @@ void NGFragmentItemsBuilder::ConvertToPhysical(WritingMode writing_mode,
 base::Optional<LogicalOffset> NGFragmentItemsBuilder::LogicalOffsetFor(
     const LayoutObject& layout_object) const {
   DCHECK_EQ(items_.size(), offsets_.size());
-  for (const std::unique_ptr<NGFragmentItem>& item : items_) {
+  for (const scoped_refptr<NGFragmentItem>& item : items_) {
     if (item->GetLayoutObject() == &layout_object)
       return offsets_[&item - items_.begin()];
   }

third_party/blink/renderer/core/layout/ng/inline/ng_fragment_items_builder.h

@@ -67,7 +67,7 @@ class CORE_EXPORT NGFragmentItemsBuilder {
   // containing block geometry for OOF-positioned nodes.
   //
   // Once this method has been called, new items cannot be added.
-  const Vector<std::unique_ptr<NGFragmentItem>>&
+  const Vector<scoped_refptr<NGFragmentItem>>&
   Items(WritingMode, TextDirection, const PhysicalSize& outer_size);
 
   // Build a |NGFragmentItems|. The builder cannot build twice because data set
@@ -84,7 +84,7 @@ class CORE_EXPORT NGFragmentItemsBuilder {
                          TextDirection direction,
                          const PhysicalSize& outer_size);
 
-  Vector<std::unique_ptr<NGFragmentItem>> items_;
+  Vector<scoped_refptr<NGFragmentItem>> items_;
   Vector<LogicalOffset> offsets_;
   String text_content_;
   String first_line_text_content_;

third_party/blink/renderer/core/layout/ng/inline/ng_inline_cursor.h

@@ -45,7 +45,7 @@ class CORE_EXPORT NGInlineCursorPosition {
   STACK_ALLOCATED();
 
  public:
-  using ItemsSpan = base::span<const std::unique_ptr<NGFragmentItem>>;
+  using ItemsSpan = base::span<const scoped_refptr<NGFragmentItem>>;
 
   const NGPaintFragment* PaintFragment() const { return paint_fragment_; }
   const NGFragmentItem* Item() const { return item_; }
@@ -170,7 +170,7 @@ class CORE_EXPORT NGInlineCursor {
   STACK_ALLOCATED();
 
  public:
-  using ItemsSpan = base::span<const std::unique_ptr<NGFragmentItem>>;
+  using ItemsSpan = base::span<const scoped_refptr<NGFragmentItem>>;
 
   explicit NGInlineCursor(const LayoutBlockFlow& block_flow);
   explicit NGInlineCursor(const NGFragmentItems& items);

third_party/blink/renderer/core/layout/ng/inline/ng_physical_text_fragment.cc

@@ -75,8 +75,10 @@ LayoutUnit NGPhysicalTextFragment::InlinePositionForOffset(
     unsigned offset,
     LayoutUnit (*round_function)(float),
     AdjustMidCluster adjust_mid_cluster) const {
-  return NGFragmentItem(*this).InlinePositionForOffset(
-      Text(), offset, round_function, adjust_mid_cluster);
+  scoped_refptr<NGFragmentItem> item =
+      base::MakeRefCounted<NGFragmentItem>(*this);
+  return item->InlinePositionForOffset(Text(), offset, round_function,
+                                       adjust_mid_cluster);
 }
 
 // TODO(yosin): We should move |NGFragmentItem::InlinePositionForOffset" to
@@ -120,14 +122,17 @@ LayoutUnit NGFragmentItem::InlinePositionForOffset(StringView text,
 
 LayoutUnit NGPhysicalTextFragment::InlinePositionForOffset(
     unsigned offset) const {
-  return NGFragmentItem(*this).InlinePositionForOffset(Text(), offset);
+  scoped_refptr<NGFragmentItem> item =
+      base::MakeRefCounted<NGFragmentItem>(*this);
+  return item->InlinePositionForOffset(Text(), offset);
 }
 
 std::pair<LayoutUnit, LayoutUnit>
 NGPhysicalTextFragment::LineLeftAndRightForOffsets(unsigned start_offset,
                                                    unsigned end_offset) const {
-  return NGFragmentItem(*this).LineLeftAndRightForOffsets(Text(), start_offset,
-                                                          end_offset);
+  scoped_refptr<NGFragmentItem> item =
+      base::MakeRefCounted<NGFragmentItem>(*this);
+  return item->LineLeftAndRightForOffsets(Text(), start_offset, end_offset);
 }
 
 // TODO(yosin): We should move |NGFragmentItem::InlinePositionForOffset" to
@@ -154,7 +159,9 @@ std::pair<LayoutUnit, LayoutUnit> NGFragmentItem::LineLeftAndRightForOffsets(
 
 PhysicalRect NGPhysicalTextFragment::LocalRect(unsigned start_offset,
                                                unsigned end_offset) const {
-  return NGFragmentItem(*this).LocalRect(Text(), start_offset, end_offset);
+  scoped_refptr<NGFragmentItem> item =
+      base::MakeRefCounted<NGFragmentItem>(*this);
+  return item->LocalRect(Text(), start_offset, end_offset);
 }
 
 // TODO(yosin): We should move |NGFragmentItem::InlinePositionForOffset" to

third_party/blink/renderer/core/layout/ng/ng_box_fragment_builder.cc

@@ -78,7 +78,7 @@ void GatherInlineContainerFragmentsFromLinebox(
 }
 
 void GatherInlineContainerFragmentsFromItems(
-    const Vector<std::unique_ptr<NGFragmentItem>>& items,
+    const Vector<scoped_refptr<NGFragmentItem>>& items,
     const PhysicalOffset& box_offset,
     NGBoxFragmentBuilder::InlineContainingBlockMap* inline_containing_block_map,
     HashMap<const LayoutObject*, LineBoxPair>* containing_linebox_map) {