[layoutng] Pass layout result by reference instead of via scoped_refptr

To avoid a useless reference add/decrease

R=eae@chromium.org

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ic1c7fe92164a4249ce7b5c8642bd5efa7a5c8e1d
Reviewed-on: https://chromium-review.googlesource.com/1217713Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590365}

third_party/blink/renderer/core/layout/layout_block_flow.cc

@@ -2532,13 +2532,14 @@ scoped_refptr<NGLayoutResult> LayoutBlockFlow::CachedLayoutResult(
   return nullptr;
 }
 
-scoped_refptr<NGLayoutResult> LayoutBlockFlow::CachedLayoutResultForTesting() {
+scoped_refptr<const NGLayoutResult>
+LayoutBlockFlow::CachedLayoutResultForTesting() {
   return nullptr;
 }
 
 void LayoutBlockFlow::SetCachedLayoutResult(const NGConstraintSpace&,
-                                            NGBreakToken*,
-                                            scoped_refptr<NGLayoutResult>) {}
+                                            const NGBreakToken*,
+                                            const NGLayoutResult&) {}
 
 void LayoutBlockFlow::SetPaintFragment(const NGBreakToken*,
                                        scoped_refptr<const NGPhysicalFragment>,

third_party/blink/renderer/core/layout/layout_block_flow.h

@@ -455,10 +455,10 @@ class CORE_EXPORT LayoutBlockFlow : public LayoutBlock {
   virtual scoped_refptr<NGLayoutResult> CachedLayoutResult(
       const NGConstraintSpace&,
       NGBreakToken*) const;
-  virtual scoped_refptr<NGLayoutResult> CachedLayoutResultForTesting();
+  virtual scoped_refptr<const NGLayoutResult> CachedLayoutResultForTesting();
   virtual void SetCachedLayoutResult(const NGConstraintSpace&,
-                                     NGBreakToken*,
-                                     scoped_refptr<NGLayoutResult>);
+                                     const NGBreakToken*,
+                                     const NGLayoutResult&);
   virtual void WillCollectInlines() {}
   virtual void SetPaintFragment(const NGBreakToken*,
                                 scoped_refptr<const NGPhysicalFragment>,

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

@@ -232,9 +232,9 @@ scoped_refptr<NGLayoutResult> LayoutNGMixin<Base>::CachedLayoutResult(
 template <typename Base>
 void LayoutNGMixin<Base>::SetCachedLayoutResult(
     const NGConstraintSpace& constraint_space,
-    NGBreakToken* break_token,
-    scoped_refptr<NGLayoutResult> layout_result) {
-  if (break_token || layout_result->Status() != NGLayoutResult::kSuccess) {
+    const NGBreakToken* break_token,
+    const NGLayoutResult& layout_result) {
+  if (break_token || layout_result.Status() != NGLayoutResult::kSuccess) {
     // We can't cache these yet
     return;
   }
@@ -242,11 +242,11 @@ void LayoutNGMixin<Base>::SetCachedLayoutResult(
     return;
 
   Base::cached_constraint_space_ = &constraint_space;
-  cached_result_ = layout_result;
+  cached_result_ = &layout_result;
 }
 
 template <typename Base>
-scoped_refptr<NGLayoutResult>
+scoped_refptr<const NGLayoutResult>
 LayoutNGMixin<Base>::CachedLayoutResultForTesting() {
   return cached_result_;
 }

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

@@ -62,10 +62,10 @@ class LayoutNGMixin : public Base {
       NGBreakToken*) const override;
 
   void SetCachedLayoutResult(const NGConstraintSpace&,
-                             NGBreakToken*,
-                             scoped_refptr<NGLayoutResult>) override;
+                             const NGBreakToken*,
+                             const NGLayoutResult&) override;
   // For testing only.
-  scoped_refptr<NGLayoutResult> CachedLayoutResultForTesting() override;
+  scoped_refptr<const NGLayoutResult> CachedLayoutResultForTesting() override;
 
   NGPaintFragment* PaintFragment() const override {
     return paint_fragment_.get();
@@ -100,7 +100,7 @@ class LayoutNGMixin : public Base {
 
   std::unique_ptr<NGInlineNodeData> ng_inline_node_data_;
 
-  scoped_refptr<NGLayoutResult> cached_result_;
+  scoped_refptr<const NGLayoutResult> cached_result_;
   scoped_refptr<NGPaintFragment> paint_fragment_;
 
   friend class NGBaseLayoutAlgorithmTest;

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

@@ -176,7 +176,7 @@ scoped_refptr<NGLayoutResult> NGBlockNode::Layout(
       // In particular, that fragment would have an incorrect offset if we
       // don't re-set the result here.
       ToLayoutBlockFlow(box_)->SetCachedLayoutResult(
-          constraint_space, break_token, layout_result);
+          constraint_space, break_token, *layout_result);
       if (!constraint_space.IsIntermediateLayout() && first_child &&
           first_child.IsInline()) {
         block_flow->UpdatePaintFragmentFromCachedLayoutResult(
@@ -256,7 +256,7 @@ void NGBlockNode::FinishLayout(const NGConstraintSpace& constraint_space,
   if (box_->IsLayoutNGMixin()) {
     LayoutBlockFlow* block_flow = ToLayoutBlockFlow(box_);
     block_flow->SetCachedLayoutResult(constraint_space, break_token,
-                                      layout_result);
+                                      *layout_result);
     NGLayoutInputNode first_child = FirstChild();
     if (first_child && first_child.IsInline()) {
       CopyFragmentDataToLayoutBoxForInlineChildren(

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

@@ -60,7 +60,7 @@ TEST_F(NGOutOfFlowLayoutPartTest, FixedInsideAbs) {
   LayoutBlockFlow* block_flow = ToLayoutBlockFlow(rel->GetLayoutObject());
   scoped_refptr<NGConstraintSpace> space =
       NGConstraintSpace::CreateFromLayoutObject(*block_flow);
-  scoped_refptr<NGLayoutResult> result =
+  scoped_refptr<const NGLayoutResult> result =
       block_flow->CachedLayoutResultForTesting();
   EXPECT_TRUE(result);
   EXPECT_EQ(result->OutOfFlowPositionedDescendants().size(), (size_t)2);