[mathml] Make NGMathRowLayoutAlgorithm store margins

Make NGMathRowLayoutAlgorithm store margins. To help collect
the margins per child, add ChildWithOffsetAndMargins, based on
NGContainerFragmentBuilder::ChildWithOffset but with added
margin information.

Bug: 6606
Change-Id: Ib546caa720d982c37843717904f06c4c85bbe95c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2257894
Commit-Queue: Rob Buis <rbuis@igalia.com>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782588}

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

@@ -38,7 +38,7 @@ NGMathRowLayoutAlgorithm::NGMathRowLayoutAlgorithm(
 }
 
 void NGMathRowLayoutAlgorithm::LayoutRowItems(
-    NGContainerFragmentBuilder::ChildrenVector* children,
+    ChildrenVector* children,
     LayoutUnit* max_row_block_baseline,
     LogicalSize* row_total_size) {
   LayoutUnit inline_offset, max_row_ascent, max_row_descent;
@@ -74,8 +74,9 @@ void NGMathRowLayoutAlgorithm::LayoutRowItems(
     // TODO(rbuis): Operators can add lspace and rspace.
 
     children->emplace_back(
+        To<NGBlockNode>(child), margins,
         LogicalOffset{inline_offset, margins.block_start - ascent},
-        &physical_fragment);
+        std::move(&physical_fragment));
 
     inline_offset += fragment.InlineSize() + margins.inline_end;
 
@@ -99,7 +100,7 @@ scoped_refptr<const NGLayoutResult> NGMathRowLayoutAlgorithm::Layout() {
 
   const LogicalSize border_box_size = container_builder_.InitialBorderBoxSize();
 
-  NGContainerFragmentBuilder::ChildrenVector children;
+  ChildrenVector children;
   LayoutRowItems(&children, &max_row_block_baseline, &max_row_size);
 
   // Add children taking into account centering, baseline and
@@ -110,10 +111,12 @@ scoped_refptr<const NGLayoutResult> NGMathRowLayoutAlgorithm::Layout() {
 
   LogicalOffset adjust_offset = BorderScrollbarPadding().StartOffset();
   adjust_offset += LogicalOffset{center_offset, max_row_block_baseline};
-  for (auto& child : children) {
-    child.offset += adjust_offset;
+  for (auto& child_data : children) {
+    child_data.offset += adjust_offset;
     container_builder_.AddChild(
-        To<NGPhysicalContainerFragment>(*child.fragment), child.offset);
+        To<NGPhysicalContainerFragment>(*child_data.fragment),
+        child_data.offset);
+    child_data.child.StoreMargins(ConstraintSpace(), child_data.margins);
   }
 
   container_builder_.SetBaseline(adjust_offset.block_offset);

third_party/blink/renderer/core/layout/ng/mathml/ng_math_row_layout_algorithm.h

@@ -19,17 +19,34 @@ class CORE_EXPORT NGMathRowLayoutAlgorithm
                                NGBoxFragmentBuilder,
                                NGBlockBreakToken> {
  public:
-  NGMathRowLayoutAlgorithm(const NGLayoutAlgorithmParams& params);
-
- protected:
-  void LayoutRowItems(NGContainerFragmentBuilder::ChildrenVector*,
-                      LayoutUnit* max_row_block_baseline,
-                      LogicalSize* row_total_size);
+  explicit NGMathRowLayoutAlgorithm(const NGLayoutAlgorithmParams& params);
+
+  struct ChildWithOffsetAndMargins {
+    DISALLOW_NEW();
+    ChildWithOffsetAndMargins(const NGBlockNode& child,
+                              const NGBoxStrut& margins,
+                              LogicalOffset offset,
+                              scoped_refptr<const NGPhysicalFragment> fragment)
+        : child(child),
+          margins(margins),
+          offset(offset),
+          fragment(std::move(fragment)) {}
+
+    NGBlockNode child;
+    NGBoxStrut margins;
+    LogicalOffset offset;
+    scoped_refptr<const NGPhysicalFragment> fragment;
+  };
+  typedef Vector<ChildWithOffsetAndMargins, 4> ChildrenVector;
 
  private:
   scoped_refptr<const NGLayoutResult> Layout() final;
 
   MinMaxSizesResult ComputeMinMaxSizes(const MinMaxSizesInput&) const final;
+
+  void LayoutRowItems(ChildrenVector*,
+                      LayoutUnit* max_row_block_baseline,
+                      LogicalSize* row_total_size);
 };
 
 }  // namespace blink