[LayoutNG] Compute baseline from fragment tree

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc

Index: third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc
index c1792201e175ec5e1339ef780b5eb4ef3216216a..330a8b93e2986640ca975447bd3a409431e3296d 100644
--- a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc
+++ b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc
@@ -4,6 +4,7 @@
 
 #include "core/layout/ng/inline/ng_inline_layout_algorithm.h"
 
+#include "core/layout/ng/inline/ng_baseline.h"
 #include "core/layout/ng/inline/ng_bidi_paragraph.h"
 #include "core/layout/ng/inline/ng_inline_break_token.h"
 #include "core/layout/ng/inline/ng_inline_node.h"
@@ -287,25 +288,15 @@ NGInlineBoxState* NGInlineLayoutAlgorithm::PlaceAtomicInline(
   NGInlineBoxState* box =
       box_states_.OnOpenTag(item, *item_result, line_box, position);
 
-  // For replaced elements, inline-block elements, and inline-table elements,
-  // the height is the height of their margin box.
-  // https://drafts.csswg.org/css2/visudet.html#line-height
   NGBoxFragment fragment(
       ConstraintSpace().WritingMode(),
       ToNGPhysicalBoxFragment(
           item_result->layout_result->PhysicalFragment().Get()));
-  LayoutUnit block_size =
-      fragment.BlockSize() + item_result->margins.BlockSum();
-
-  // TODO(kojii): Add baseline position to NGPhysicalFragment.
-  LayoutBox* layout_box = ToLayoutBox(item.GetLayoutObject());
-  LineDirectionMode line_direction_mode =
-      IsHorizontalWritingMode() ? LineDirectionMode::kHorizontalLine
-                                : LineDirectionMode::kVerticalLine;
-  LayoutUnit baseline_offset(layout_box->BaselinePosition(
-      baseline_type_, line_info.UseFirstLineStyle(), line_direction_mode));
-
-  NGLineHeightMetrics metrics(baseline_offset, block_size - baseline_offset);
+  NGLineHeightMetrics metrics = fragment.BaselineMetrics(
+      {line_info.UseFirstLineStyle()
+           ? NGBaselineAlgorithmType::kAtomicInlineForFirstLine
+           : NGBaselineAlgorithmType::kAtomicInline,
+       baseline_type_});
   box->metrics.Unite(metrics);
 
   // TODO(kojii): Figure out what to do with OOF in NGLayoutResult.
@@ -315,7 +306,7 @@ NGInlineBoxState* NGInlineLayoutAlgorithm::PlaceAtomicInline(
   // |fragment| directly. Currently |CopyFragmentDataToLayoutBlockFlow|
   // requires a text fragment.
   text_builder->SetDirection(style.Direction());
-  text_builder->SetSize({fragment.InlineSize(), block_size});
+  text_builder->SetSize({fragment.InlineSize(), metrics.LineHeight()});
   LayoutUnit line_top = item_result->margins.block_start - metrics.ascent;
   RefPtr<NGPhysicalTextFragment> text_fragment = text_builder->ToTextFragment(
       item_result->item_index, item_result->start_offset,
@@ -406,6 +397,50 @@ LayoutUnit NGInlineLayoutAlgorithm::ComputeContentSize(
   return content_size;
 }
 
+// Add a baseline from a child line box.
+// @return false if the specified child is not a line box.
+bool NGInlineLayoutAlgorithm::AddBaseline(const NGBaselineRequest& request,
+                                          unsigned child_index) {
+  const NGPhysicalFragment* child =
+      container_builder_.Children()[child_index].Get();
+  if (!child->IsLineBox())
+    return false;
+
+  const NGPhysicalLineBoxFragment* line_box =
+      ToNGPhysicalLineBoxFragment(child);
+  LayoutUnit offset = line_box->BaselinePosition(request.baseline_type);
+  container_builder_.AddBaseline(
+      request.algorithm_type, request.baseline_type,
+      offset + container_builder_.Offsets()[child_index].block_offset);
+  return true;
+}
+
+// Compute requested baselines from child line boxes.
+void NGInlineLayoutAlgorithm::PropagateBaselinesFromChildren() {
+  const Vector<NGBaselineRequest>& requests =
+      ConstraintSpace().BaselineRequests();
+  if (requests.IsEmpty())
+    return;
+
+  for (const auto& request : requests) {
+    switch (request.algorithm_type) {
+      case NGBaselineAlgorithmType::kAtomicInline:
+      case NGBaselineAlgorithmType::kAtomicInlineForFirstLine:
+        for (unsigned i = container_builder_.Children().size(); i--;) {
+          if (AddBaseline(request, i))
+            break;
+        }
+        break;
+      case NGBaselineAlgorithmType::kFirstLine:
+        for (unsigned i = 0; i < container_builder_.Children().size(); i++) {
+          if (AddBaseline(request, i))
+            break;
+        }
+        break;
+    }
+  }
+}
+
 RefPtr<NGLayoutResult> NGInlineLayoutAlgorithm::Layout() {
   // Line boxes should start at (0,0).
   // The parent NGBlockLayoutAlgorithm places the anonymous wrapper using the
@@ -429,6 +464,8 @@ RefPtr<NGLayoutResult> NGInlineLayoutAlgorithm::Layout() {
     container_builder_.SetEndMarginStrut(ConstraintSpace().MarginStrut());
   }
 
+  PropagateBaselinesFromChildren();
+
   return container_builder_.ToBoxFragment();
 }