[FlexNG] Add AddOutOfFlowChildCandidate which accepts "edge" parameters.

This (somewhat) refactors the AddOutOfFlowChildCandidate into two variants:
 1) For the inline-level OOF case.
 2) For the block-level OOF, added additional "edge" paramaeters.

There should be no behaviour change.

Bug: 845235
Change-Id: If3957078afca7cc0f9175198837a06f0f2badadb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1931676
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Aleks Totic <atotic@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721686}

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

@@ -629,8 +629,8 @@ NGInlineLayoutStateStack::BoxData::CreateBoxFragment(
       // position to be relative to this fragment.
       LogicalOffset static_offset = child.offset - offset;
 
-      box.AddOutOfFlowChildCandidate(oof_box, static_offset,
-                                     child.container_direction);
+      box.AddOutOfFlowInlineChildCandidate(oof_box, static_offset,
+                                           child.container_direction);
       child.out_of_flow_positioned_box = nullptr;
       continue;
     }

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

@@ -100,7 +100,7 @@ void NGLineBoxFragmentBuilder::AddChildren(ChildList& children) {
       AddChild(std::move(child.fragment), child.offset);
       DCHECK(!child.fragment);
     } else if (child.out_of_flow_positioned_box) {
-      AddOutOfFlowChildCandidate(
+      AddOutOfFlowInlineChildCandidate(
           NGBlockNode(ToLayoutBox(child.out_of_flow_positioned_box)),
           child.offset, child.container_direction);
       child.out_of_flow_positioned_box = nullptr;
@@ -127,7 +127,7 @@ void NGLineBoxFragmentBuilder::PropagateChildrenData(ChildList& children) {
       continue;
     }
     if (child.out_of_flow_positioned_box) {
-      AddOutOfFlowChildCandidate(
+      AddOutOfFlowInlineChildCandidate(
           NGBlockNode(ToLayoutBox(child.out_of_flow_positioned_box)),
           child.offset, child.container_direction);
       child.out_of_flow_positioned_box = nullptr;

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

@@ -193,24 +193,28 @@ LogicalOffset NGContainerFragmentBuilder::GetChildOffset(
 void NGContainerFragmentBuilder::AddOutOfFlowChildCandidate(
     NGBlockNode child,
     const LogicalOffset& child_offset,
-    base::Optional<TextDirection> container_direction) {
+    NGLogicalStaticPosition::InlineEdge inline_edge,
+    NGLogicalStaticPosition::BlockEdge block_edge) {
   DCHECK(child);
-  DCHECK(layout_object_ && !layout_object_->IsLayoutInline() ||
-         container_direction)
-      << "container_direction must only be set for inline-level OOF children.";
+
+  oof_positioned_candidates_.emplace_back(
+      child, NGLogicalStaticPosition{child_offset, inline_edge, block_edge});
+}
+
+void NGContainerFragmentBuilder::AddOutOfFlowInlineChildCandidate(
+    NGBlockNode child,
+    const LogicalOffset& child_offset,
+    TextDirection inline_container_direction) {
+  DCHECK(node_.IsInline() || layout_object_->IsLayoutInline());
 
   // As all inline-level fragments are built in the line-logical coordinate
   // system (Direction() is kLtr), we need to know the direction of the
   // parent element to correctly determine an OOF childs static position.
-  TextDirection direction = container_direction.value_or(TextDirection::kLtr);
-
-  oof_positioned_candidates_.emplace_back(
-      child,
-      NGLogicalStaticPosition{
-          child_offset,
-          IsLtr(direction) ? NGLogicalStaticPosition::InlineEdge::kInlineStart
-                           : NGLogicalStaticPosition::InlineEdge::kInlineEnd,
-          NGLogicalStaticPosition::BlockEdge::kBlockStart});
+  AddOutOfFlowChildCandidate(child, child_offset,
+                             IsLtr(inline_container_direction)
+                                 ? NGLogicalStaticPosition::kInlineStart
+                                 : NGLogicalStaticPosition::kInlineEnd,
+                             NGLogicalStaticPosition::kBlockStart);
 }
 
 void NGContainerFragmentBuilder::AddOutOfFlowDescendant(

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

@@ -114,13 +114,20 @@ class CORE_EXPORT NGContainerFragmentBuilder : public NGFragmentBuilder {
   // NGOutOfFlowLayoutPart(container_style, builder).Run();
   //
   // See layout part for builder interaction.
-  //
-  // @param direction: default candidate direction is builder's direction.
-  // Pass in direction if candidates direction does not match.
-  void AddOutOfFlowChildCandidate(
+  void AddOutOfFlowChildCandidate(NGBlockNode,
+                                  const LogicalOffset& child_offset,
+                                  NGLogicalStaticPosition::InlineEdge =
+                                      NGLogicalStaticPosition::kInlineStart,
+                                  NGLogicalStaticPosition::BlockEdge =
+                                      NGLogicalStaticPosition::kBlockStart);
+
+  // This should only be used for inline-level OOF-positioned nodes.
+  // |inline_container_direction| is the current text direction for determining
+  // the correct static-position.
+  void AddOutOfFlowInlineChildCandidate(
       NGBlockNode,
       const LogicalOffset& child_offset,
-      base::Optional<TextDirection> container_direction = base::nullopt);
+      TextDirection inline_container_direction);
 
   void AddOutOfFlowDescendant(
       const NGLogicalOutOfFlowPositionedNode& descendant);