[LayoutNG] Position descendants in inline containing block.

Part 4 of 4 of inline containing block for OOF descendants
https://chromium-review.googlesource.com/c/chromium/src/+/777707

Geometry of computing the containing block coordinates is complex.

In the old code, all containing block geometry was stored as members of
NGOutOfFlowLayoutPart.

With inline containing blocks, each inline-cb can have a different geometry.
Code was refactored so that cb geometry is configurable per descendant.

Bug: 740993
Change-Id: I3dd392472081ac6b09dd6a2540d142ba9966f3a6
Reviewed-on: https://chromium-review.googlesource.com/818333
Commit-Queue: Aleks Totic <atotic@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523635}

third_party/WebKit/Source/core/layout/ng/ng_block_node.cc

@@ -463,9 +463,12 @@ void NGBlockNode::CopyChildFragmentPosition(
   // We should only be positioning children which are relative to ourselves.
   // The flow thread, however, is invisible to LayoutNG, so we need to make
   // an exception there.
-  DCHECK(box_ == layout_box->ContainingBlock() ||
-         (layout_box->ContainingBlock()->IsLayoutFlowThread() &&
-          box_ == layout_box->ContainingBlock()->ContainingBlock()));
+  DCHECK(
+      box_ == layout_box->ContainingBlock() ||
+      (layout_box->ContainingBlock()->IsLayoutFlowThread() &&
+       box_ == layout_box->ContainingBlock()->ContainingBlock()) ||
+      (layout_box->ContainingBlock()->IsInline() &&  // anonymous wrapper case
+       box_->Parent() == layout_box->ContainingBlock()));
 
   // LegacyLayout flips vertical-rl horizontal coordinates before paint.
   // NGLayout flips X location for LegacyLayout compatibility.

third_party/WebKit/Source/core/layout/ng/ng_out_of_flow_layout_part.h

@@ -37,15 +37,45 @@ class CORE_EXPORT NGOutOfFlowLayoutPart {
   void Run(bool update_legacy = true);
 
  private:
+  // Information needed to position descendant within a containing block.
+  // Geometry expressed here is complicated:
+  // There are two types of containing blocks:
+  // 1) Default containing block (DCB)
+  //    Containing block passed in NGOutOfFlowLayoutPart constructor.
+  //    It is the block element inside which this algorighm runs.
+  //    All OOF descendants not in inline containing block are placed in DCB.
+  // 2) Inline containing block
+  //    OOF descendants might be positioned wrt inline containing block.
+  //    Inline containing block is positioned wrt default containing block.
+  struct ContainingBlockInfo {
+    STACK_ALLOCATED();
+    // Containing block style.
+    const ComputedStyle* style;
+    // Logical in containing block coordinates.
+    NGLogicalSize content_size;
+    // Content offset wrt border box.
+    NGLogicalOffset content_offset;
+    // Physical content offset wrt border box.
+    NGPhysicalOffset content_physical_offset;
+    // Logical offset wrt default containing block.
+    NGLogicalOffset default_container_offset;
+  };
+
+  ContainingBlockInfo GetContainingBlockInfo(
+      const NGOutOfFlowPositionedDescendant&) const;
+
+  void ComputeInlineContainingBlocks(Vector<NGOutOfFlowPositionedDescendant>);
+
   scoped_refptr<NGLayoutResult> LayoutDescendant(
-      NGBlockNode descendant,
-      NGStaticPosition static_position,
+      const NGOutOfFlowPositionedDescendant&,
       NGLogicalOffset* offset);
 
-  bool IsContainingBlockForDescendant(const ComputedStyle& descendant_style);
+  bool IsContainingBlockForDescendant(
+      const NGOutOfFlowPositionedDescendant& descendant);
 
   scoped_refptr<NGLayoutResult> GenerateFragment(
       NGBlockNode node,
+      const ContainingBlockInfo&,
       const Optional<LayoutUnit>& block_estimate,
       const NGAbsolutePhysicalPosition node_position);
 
@@ -54,10 +84,12 @@ class CORE_EXPORT NGOutOfFlowLayoutPart {
 
   bool contains_absolute_;
   bool contains_fixed_;
+  ContainingBlockInfo default_containing_block_;
   NGLogicalOffset content_offset_;
   NGPhysicalOffset content_physical_offset_;
   NGLogicalSize container_size_;
   NGPhysicalSize icb_size_;
+  HashMap<const LayoutObject*, ContainingBlockInfo> containing_blocks_map_;
 };
 
 }  // namespace blink