WIP version of new margin collapsing logic + support of empty blocks with floats

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

Index: third_party/WebKit/Source/core/layout/ng/ng_box_fragment.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_box_fragment.cc b/third_party/WebKit/Source/core/layout/ng/ng_box_fragment.cc
index cda163878d7a046513c72502aa33c946e166e3e8..52ff3417eeaec86aa566c6283a8bafe906a7a6c4 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_box_fragment.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_box_fragment.cc
@@ -9,12 +9,17 @@
 
 namespace blink {
 
-NGDeprecatedMarginStrut NGBoxFragment::MarginStrut() const {
+const WTF::Optional<NGLogicalOffset>& NGBoxFragment::BfcOffset() const {
+  // TODO(glebl): should respect the writing mode here.
+  return toNGPhysicalBoxFragment(physical_fragment_)->BfcOffset();
+}
+
+const NGMarginStrut& NGBoxFragment::EndMarginStrut() const {
   WRITING_MODE_IGNORED(
       "Accessing the margin strut is fine here. Changing the writing mode"
-      "establishes a new formatting context, for which a margin strut is never"
-      "set for a fragment.");
-  return toNGPhysicalBoxFragment(physical_fragment_)->MarginStrut();
+      "establishes a new formatting context, for which a margin strut is"
+      "never set for a fragment.");
+  return toNGPhysicalBoxFragment(physical_fragment_)->EndMarginStrut();
 }
 
 }  // namespace blink