[FragmentItem] Remove |NGFragmentItem::ItemsFor|

This function was added to be the same interface as
|NGPaintFragment::InlineFragmentsFor|, but as
|NGInlineCursor| evoles, it has the same functionality
though |MoveTo(const LayoutObject&)| and
|MoveToNextForSameLayoutObject()|.

Now we prefer |NGInlineCurosr| for all traversals that this
patch removes |ItemsFor()| function and switch all usages to
|NGInlineCusror|.

Bug: 982194
Change-Id: Ia9dfd4f608d8cfc2c5f6ccc5b40b1e1dda0876f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2022445Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735349}

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

@@ -281,7 +281,11 @@ PhysicalRect NGFragmentItem::LocalVisualRectFor(
   DCHECK(layout_object.IsInLayoutNGInlineFormattingContext());
 
   PhysicalRect visual_rect;
-  for (const NGFragmentItem& item : ItemsFor(layout_object)) {
+  NGInlineCursor cursor;
+  for (cursor.MoveTo(layout_object); cursor;
+       cursor.MoveToNextForSameLayoutObject()) {
+    DCHECK(cursor.Current().Item());
+    const NGFragmentItem& item = *cursor.Current().Item();
     if (UNLIKELY(item.IsHiddenForPaint()))
       continue;
     PhysicalRect child_visual_rect = item.SelfInkOverflow();
@@ -445,49 +449,6 @@ unsigned NGFragmentItem::TextOffsetForPoint(
   return inline_offset <= size.inline_size / 2 ? StartOffset() : EndOffset();
 }
 
-NGFragmentItem::ItemsForLayoutObject NGFragmentItem::ItemsFor(
-    const LayoutObject& layout_object) {
-  DCHECK(layout_object.IsInLayoutNGInlineFormattingContext());
-  DCHECK(layout_object.IsText() || layout_object.IsLayoutInline() ||
-         (layout_object.IsBox() && layout_object.IsInline()));
-
-  if (const LayoutBlockFlow* block_flow =
-          layout_object.RootInlineFormattingContext()) {
-    if (const NGPhysicalBoxFragment* fragment = block_flow->CurrentFragment()) {
-      if (wtf_size_t index = layout_object.FirstInlineFragmentItemIndex()) {
-        const auto& items = fragment->Items()->Items();
-        return ItemsForLayoutObject(items, index, items[index].get());
-      }
-      // TODO(yosin): Once we update all usages of |FirstInlineFragment()|,
-      // we should get rid of below code.
-      if (const NGFragmentItems* items = fragment->Items()) {
-        for (unsigned i = 0; i < items->Items().size(); ++i) {
-          const NGFragmentItem* item = items->Items()[i].get();
-          if (item->GetLayoutObject() == &layout_object)
-            return ItemsForLayoutObject(items->Items(), i, item);
-        }
-      }
-    }
-  }
-
-  return ItemsForLayoutObject();
-}
-
-NGFragmentItem::ItemsForLayoutObject::Iterator&
-NGFragmentItem::ItemsForLayoutObject::Iterator::operator++() {
-  // TODO(kojii): This is a hot function needed by paint and several other
-  // operations. Make this fast, by not iterating.
-  if (!current_)
-    return *this;
-  if (!current_->delta_to_next_for_same_layout_object_) {
-    current_ = nullptr;
-    return *this;
-  }
-  index_ += current_->delta_to_next_for_same_layout_object_;
-  current_ = (*items_)[index_].get();
-  return *this;
-}
-
 std::ostream& operator<<(std::ostream& ostream, const NGFragmentItem& item) {
   ostream << "{";
   switch (item.Type()) {

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

@@ -177,52 +177,6 @@ class CORE_EXPORT NGFragmentItem : public DisplayItemClient {
   IntRect VisualRect() const override;
   IntRect PartialInvalidationVisualRect() const override;
 
-  // Find |NGFragmentItem|s that are associated with a |LayoutObject|.
-  class CORE_EXPORT ItemsForLayoutObject {
-    STACK_ALLOCATED();
-
-   public:
-    ItemsForLayoutObject() = default;
-    ItemsForLayoutObject(const Vector<std::unique_ptr<NGFragmentItem>>& items,
-                         unsigned first_index,
-                         const NGFragmentItem* first_item)
-        : items_(&items), first_item_(first_item), first_index_(first_index) {}
-
-    bool IsEmpty() const { return !items_; }
-
-    class CORE_EXPORT Iterator {
-     public:
-      Iterator(const Vector<std::unique_ptr<NGFragmentItem>>* items,
-               unsigned index,
-               const NGFragmentItem* item)
-          : current_(item), items_(items), index_(index) {}
-      const NGFragmentItem& operator*() const { return *current_; }
-      const NGFragmentItem& operator->() const { return *current_; }
-      Iterator& operator++();
-      bool operator==(const Iterator& other) const {
-        return current_ == other.current_;
-      }
-      bool operator!=(const Iterator& other) const {
-        return current_ != other.current_;
-      }
-
-     private:
-      const NGFragmentItem* current_;
-      const Vector<std::unique_ptr<NGFragmentItem>>* items_;
-      unsigned index_;
-    };
-    using iterator = Iterator;
-    iterator begin() const {
-      return Iterator(items_, first_index_, first_item_);
-    }
-    iterator end() const { return Iterator(nullptr, 0, nullptr); }
-
-   private:
-    const Vector<std::unique_ptr<NGFragmentItem>>* items_;
-    const NGFragmentItem* first_item_;
-    unsigned first_index_;
-  };
-  static ItemsForLayoutObject ItemsFor(const LayoutObject& layout_object);
   static PhysicalRect LocalVisualRectFor(const LayoutObject& layout_object);
 
   // Re-compute the ink overflow for the |cursor| until its end.

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

@@ -8,6 +8,7 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/renderer/core/layout/layout_block_flow.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_fragment_items.h"
+#include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_cursor.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_layout_test.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_physical_box_fragment.h"
 
@@ -22,9 +23,12 @@ class NGFragmentItemTest : public NGLayoutTest,
 
   Vector<const NGFragmentItem*> ItemsForAsVector(
       const LayoutObject& layout_object) {
-    const auto items = NGFragmentItem::ItemsFor(layout_object);
     Vector<const NGFragmentItem*> list;
-    for (const NGFragmentItem& item : items) {
+    NGInlineCursor cursor;
+    for (cursor.MoveTo(layout_object); cursor;
+         cursor.MoveToNextForSameLayoutObject()) {
+      DCHECK(cursor.Current().Item());
+      const NGFragmentItem& item = *cursor.Current().Item();
       EXPECT_EQ(item.GetLayoutObject(), &layout_object);
       list.push_back(&item);
     }

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

@@ -124,7 +124,7 @@ class CORE_EXPORT NGInlineCursor {
   // or after last fragment in tree.
   bool IsNull() const { return !Current(); }
   bool IsNotNull() const { return Current(); }
-  explicit operator bool() const { return Current(); }
+  operator bool() const { return Current(); }
 
   // True if fragment at the current position can have children.
   bool CanHaveChildren() const;

third_party/blink/renderer/core/paint/ng/ng_inline_box_fragment_painter.cc

@@ -34,7 +34,14 @@ inline bool HasMultiplePaintFragments(const LayoutObject& layout_object) {
 }
 
 inline bool HasMultipleFragmentItems(const LayoutObject& layout_object) {
-  return HasMultipleItems(NGFragmentItem::ItemsFor(layout_object));
+  NGInlineCursor cursor;
+  cursor.MoveTo(layout_object);
+  DCHECK(cursor);
+  if (cursor) {
+    cursor.MoveToNextForSameLayoutObject();
+    return cursor;
+  }
+  return false;
 }
 
 }  // namespace