Remove uses of FragmentItem runtime flag in NGBlockLayoutAlgorithm

Also change |NGInlineChildLayoutContext| to own
|NGFragmentItemsBuilder| because it is always needed when
|FragmentItem| is enabled. This simplifies allocations and
call sites slightly.

Bug: 1154531
Change-Id: I7458f80978bc9ef7348fb6836f44ca9adf4574f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2592568
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837046}

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

@@ -11,9 +11,10 @@ namespace blink {
 namespace {
 
 struct SameSizeAsNGInlineChildLayoutContext {
+  NGFragmentItemsBuilder items_builder_;
   NGLogicalLineItems line_items_;
   base::Optional<NGInlineLayoutStateStack> box_states_;
-  void* pointers[2];
+  void* pointers[1];
   unsigned number;
   Vector<scoped_refptr<const NGBlockBreakToken>> propagated_float_break_tokens_;
 };
@@ -26,7 +27,10 @@ static_assert(
 
 }  // namespace
 
-NGInlineChildLayoutContext::NGInlineChildLayoutContext() = default;
+NGInlineChildLayoutContext::NGInlineChildLayoutContext(
+    const NGInlineNode& node,
+    WritingDirectionMode writing_direction)
+    : items_builder_(node, writing_direction) {}
 NGInlineChildLayoutContext::~NGInlineChildLayoutContext() = default;
 
 NGInlineLayoutStateStack*

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

@@ -24,16 +24,11 @@ class CORE_EXPORT NGInlineChildLayoutContext {
   STACK_ALLOCATED();
 
  public:
-  NGInlineChildLayoutContext();
+  NGInlineChildLayoutContext(const NGInlineNode& node,
+                             WritingDirectionMode writing_direction);
   ~NGInlineChildLayoutContext();
 
-  NGFragmentItemsBuilder* ItemsBuilder() { return items_builder_; }
-  void SetItemsBuilder(NGFragmentItemsBuilder* builder) {
-    DCHECK(!items_builder_ || !builder);
-    items_builder_ = builder;
-    if (builder)
-      builder->AddLogicalLineItemsPool(&logical_line_items_);
-  }
+  NGFragmentItemsBuilder* ItemsBuilder() { return &items_builder_; }
 
   // Returns an instance of |NGLogicalLineItems|. This is reused when laying out
   // the next line.
@@ -65,9 +60,7 @@ class CORE_EXPORT NGInlineChildLayoutContext {
   void PropagateBreakToken(scoped_refptr<const NGBlockBreakToken>);
 
  private:
-  // TODO(kojii): Probably better to own |NGInlineChildLayoutContext|. While we
-  // transit, allocating separately is easier.
-  NGFragmentItemsBuilder* items_builder_ = nullptr;
+  NGFragmentItemsBuilder items_builder_;
 
   NGLogicalLineItems logical_line_items_;
 

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

@@ -52,14 +52,12 @@ TEST_F(NGInlineLayoutAlgorithmTest, BreakToken) {
   builder.SetAvailableSize(size);
   NGConstraintSpace constraint_space = builder.ToConstraintSpace();
 
-  NGInlineChildLayoutContext context;
   NGBoxFragmentBuilder container_builder(
       block_flow, block_flow->Style(),
       block_flow->Style()->GetWritingDirection());
-  NGFragmentItemsBuilder items_builder(inline_node,
-                                       container_builder.GetWritingDirection());
-  container_builder.SetItemsBuilder(&items_builder);
-  context.SetItemsBuilder(&items_builder);
+  NGInlineChildLayoutContext context(inline_node,
+                                     container_builder.GetWritingDirection());
+  container_builder.SetItemsBuilder(context.ItemsBuilder());
   scoped_refptr<const NGLayoutResult> layout_result =
       inline_node.Layout(constraint_space, nullptr, &context);
   const auto& line1 = layout_result->PhysicalFragment();

third_party/blink/renderer/core/layout/ng/mathml/ng_math_operator_layout_algorithm.cc

@@ -44,11 +44,9 @@ scoped_refptr<const NGLayoutResult> NGMathOperatorLayoutAlgorithm::Layout() {
   DCHECK(!child.NextSibling());
   DCHECK(!child.IsOutOfFlowPositioned());
 
-  NGInlineChildLayoutContext context;
-  NGFragmentItemsBuilder items_builder(
-      To<NGInlineNode>(child), container_builder_.GetWritingDirection());
-  container_builder_.SetItemsBuilder(&items_builder);
-  context.SetItemsBuilder(&items_builder);
+  NGInlineChildLayoutContext context(To<NGInlineNode>(child),
+                                     container_builder_.GetWritingDirection());
+  container_builder_.SetItemsBuilder(context.ItemsBuilder());
   scoped_refptr<const NGLayoutResult> child_layout_result =
       To<NGInlineNode>(child).Layout(ConstraintSpace(), nullptr, &context);
   container_builder_.AddResult(*child_layout_result, {});

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

@@ -34,7 +34,6 @@
 #include "third_party/blink/renderer/core/layout/ng/ng_positioned_float.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_space_utils.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_unpositioned_float.h"
-#include "third_party/blink/renderer/core/paint/ng/ng_paint_fragment.h"
 #include "third_party/blink/renderer/core/style/computed_style.h"
 
 namespace blink {
@@ -429,26 +428,13 @@ scoped_refptr<const NGLayoutResult> NGBlockLayoutAlgorithm::Layout() {
 NOINLINE scoped_refptr<const NGLayoutResult>
 NGBlockLayoutAlgorithm::LayoutWithInlineChildLayoutContext(
     const NGLayoutInputNode& first_child) {
-  NGInlineChildLayoutContext context;
-  if (!RuntimeEnabledFeatures::LayoutNGFragmentItemEnabled())
-    return Layout(&context);
-  return LayoutWithItemsBuilder(To<NGInlineNode>(first_child), &context);
-}
-
-NOINLINE scoped_refptr<const NGLayoutResult>
-NGBlockLayoutAlgorithm::LayoutWithItemsBuilder(
-    const NGInlineNode& first_child,
-    NGInlineChildLayoutContext* context) {
-  NGFragmentItemsBuilder items_builder(
-      first_child, container_builder_.GetWritingDirection());
-  container_builder_.SetItemsBuilder(&items_builder);
-  context->SetItemsBuilder(&items_builder);
-  scoped_refptr<const NGLayoutResult> result = Layout(context);
-  // Ensure stack-allocated |NGFragmentItemsBuilder| is not used anymore.
-  // TODO(kojii): Revisit when the storage of |NGFragmentItemsBuilder| is
-  // finalized.
+  NGInlineChildLayoutContext context(To<NGInlineNode>(first_child),
+                                     container_builder_.GetWritingDirection());
+  container_builder_.SetItemsBuilder(context.ItemsBuilder());
+  scoped_refptr<const NGLayoutResult> result = Layout(&context);
+  // |NGFragmentItemsBuilder| is owned by |NGInlineChildLayoutContext| which is
+  // on stack. Make sure it is no longer referred.
   container_builder_.SetItemsBuilder(nullptr);
-  context->SetItemsBuilder(nullptr);
   return result;
 }
 
@@ -981,7 +967,6 @@ bool NGBlockLayoutAlgorithm::TryReuseFragmentsFromCache(
     NGInlineNode inline_node,
     NGPreviousInflowPosition* previous_inflow_position,
     scoped_refptr<const NGInlineBreakToken>* inline_break_token_out) {
-  DCHECK(RuntimeEnabledFeatures::LayoutNGFragmentItemEnabled());
   DCHECK(previous_result_);
   DCHECK(!inline_node.IsEmptyInline());
   DCHECK(container_builder_.BfcBlockOffset());
@@ -1601,8 +1586,7 @@ NGLayoutResult::EStatus NGBlockLayoutAlgorithm::HandleInflow(
     is_non_empty_inline = !child_inline_node->IsEmptyInline();
 
     // Add reusable line boxes from |previous_result_| if any.
-    if (is_non_empty_inline && !child_break_token && previous_result_ &&
-        RuntimeEnabledFeatures::LayoutNGFragmentItemEnabled()) {
+    if (is_non_empty_inline && !child_break_token && previous_result_) {
       if (!ResolveBfcBlockOffset(previous_inflow_position))
         return NGLayoutResult::kBfcBlockOffsetResolved;
       DCHECK(container_builder_.BfcBlockOffset());

third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.h

@@ -68,9 +68,6 @@ class CORE_EXPORT NGBlockLayoutAlgorithm
  private:
   NOINLINE scoped_refptr<const NGLayoutResult>
   LayoutWithInlineChildLayoutContext(const NGLayoutInputNode& first_child);
-  NOINLINE scoped_refptr<const NGLayoutResult> LayoutWithItemsBuilder(
-      const NGInlineNode& first_child,
-      NGInlineChildLayoutContext* context);
 
   // Lay out again, this time with a predefined good breakpoint that we
   // discovered in the first pass. This happens when we run out of space in a

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

@@ -227,13 +227,11 @@ scoped_refptr<const NGLayoutResult> NGSimplifiedLayoutAlgorithm::Layout() {
 
   // We add both items and line-box fragments for existing mechanisms to work.
   // We may revisit this in future. See also |NGBoxFragmentBuilder::AddResult|.
-  if (RuntimeEnabledFeatures::LayoutNGFragmentItemEnabled()) {
-    if (const NGFragmentItems* previous_items = previous_fragment.Items()) {
-      auto* items_builder = container_builder_.ItemsBuilder();
-      DCHECK(items_builder);
-      DCHECK_EQ(items_builder->GetWritingDirection(), writing_direction_);
-      items_builder->AddPreviousItems(previous_fragment, *previous_items);
-    }
+  if (const NGFragmentItems* previous_items = previous_fragment.Items()) {
+    auto* items_builder = container_builder_.ItemsBuilder();
+    DCHECK(items_builder);
+    DCHECK_EQ(items_builder->GetWritingDirection(), writing_direction_);
+    items_builder->AddPreviousItems(previous_fragment, *previous_items);
   }
 
   NGOutOfFlowLayoutPart(Node(), ConstraintSpace(), &container_builder_).Run();