Collapse bottom margins of a last child and its parent if parent's height=auto

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

Index: third_party/WebKit/Source/core/layout/ng/ng_units.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_units.h b/third_party/WebKit/Source/core/layout/ng/ng_units.h
index c4be357477675a71fb3df86e2c90aa5bbcbbaf2f..d2777cc3137ac2d08fb8e22002689303752363d3 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_units.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_units.h
@@ -118,7 +118,7 @@ struct NGBoxStrut {
 };
 
 // This struct is used for the margin collapsing calculation.
-struct NGMarginStrut {
+struct CORE_EXPORT NGMarginStrut {
   LayoutUnit margin_block_start;
   LayoutUnit margin_block_end;
 
@@ -127,8 +127,11 @@ struct NGMarginStrut {
 
   void AppendMarginBlockStart(const LayoutUnit& value);
   void AppendMarginBlockEnd(const LayoutUnit& value);
+  void SetMarginBlockEnd(const LayoutUnit& value);
 
   String ToString() const;
+
+  bool operator==(const NGMarginStrut& other) const;
 };
 
 inline std::ostream& operator<<(std::ostream& stream,