Top down version of algorithm to position margins and floats in LayoutNG

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

Index: third_party/WebKit/Source/core/layout/ng/ng_constraint_space_builder.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_constraint_space_builder.cc b/third_party/WebKit/Source/core/layout/ng/ng_constraint_space_builder.cc
index ac99cdd46c2c8c7e3304277d7a1a78bca7833097..392ad35373bf40261a2790722b09cdb016b8809a 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_constraint_space_builder.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_constraint_space_builder.cc
@@ -23,6 +23,7 @@ NGConstraintSpaceBuilder::NGConstraintSpaceBuilder(
       fragmentation_type_(parent_space->BlockFragmentationType()),
       is_new_fc_(parent_space->IsNewFormattingContext()),
       text_direction_(static_cast<unsigned>(parent_space->Direction())),
+      bfc_offset_(parent_space->bfc_offset_),
       exclusions_(parent_space->Exclusions()) {}
 
 NGConstraintSpaceBuilder::NGConstraintSpaceBuilder(NGWritingMode writing_mode)
@@ -57,6 +58,12 @@ NGConstraintSpaceBuilder& NGConstraintSpaceBuilder::SetTextDirection(
   return *this;
 }
 
+NGConstraintSpaceBuilder& NGConstraintSpaceBuilder::SetMarginStrut(
+    const NGMarginStrut& margin_strut) {
+  margin_strut_ = margin_strut;
+  return *this;
+}
+
 NGConstraintSpaceBuilder& NGConstraintSpaceBuilder::SetIsFixedSizeInline(
     bool is_fixed_size_inline) {
   is_fixed_size_inline_ = is_fixed_size_inline;
@@ -131,7 +138,8 @@ NGConstraintSpace* NGConstraintSpaceBuilder::ToConstraintSpace() {
         is_inline_direction_triggers_scrollbar_,
         is_block_direction_triggers_scrollbar_,
         static_cast<NGFragmentationType>(fragmentation_type_), is_new_fc_,
-        exclusions);
+        is_new_fc_ ? NGMarginStrut() : margin_strut_,
+        is_new_fc_ ? NGLogicalOffset() : bfc_offset_, exclusions);

[ikilpatrick, 2017/01/26 00:49:58]

TODO ian think.... 

[Gleb Lanbin, 2017/01/31 00:25:01]

sorry, probably I miss the context here. Can you elaborate what kind of work is
required here so I can add a TODO. 

   }
 
   return new NGConstraintSpace(
@@ -145,7 +153,7 @@ NGConstraintSpace* NGConstraintSpaceBuilder::ToConstraintSpace() {
       is_block_direction_triggers_scrollbar_,
       is_inline_direction_triggers_scrollbar_,
       static_cast<NGFragmentationType>(fragmentation_type_), is_new_fc_,
-      exclusions);
+      margin_strut_, bfc_offset_, exclusions);
 }
 
 }  // namespace blink