Fix incorrectly calculated content_size for fragments that create new FC

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

Index: third_party/WebKit/Source/core/layout/ng/ng_units.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_units.cc b/third_party/WebKit/Source/core/layout/ng/ng_units.cc
index bec0be56fa5bf76fa1712c4429e0ff315608a529..5c60d03a4bd97107d4f91fc0903f1864cc27ae54 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_units.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_units.cc
@@ -71,6 +71,10 @@ bool NGBoxStrut::operator==(const NGBoxStrut& other) const {
          std::tie(inline_start, inline_end, block_start, block_end);
 }
 
+LayoutUnit NGMarginStrut::BlockEndSum() const {
+  return margin_block_end + negative_margin_block_end;
+}
+
 void NGMarginStrut::AppendMarginBlockStart(const LayoutUnit& value) {
   if (value < 0) {
     negative_margin_block_start =