[LayoutNG] Fix orthogonal writing mode child margin strut from being used in collapsing margins cal…

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

Index: third_party/WebKit/Source/core/layout/ng/ng_fragment.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_fragment.cc b/third_party/WebKit/Source/core/layout/ng/ng_fragment.cc
index 4085e380af9aea6c8746769477c7eb5125ff9ab5..ca9dcb63a722bd2fbd1c173c590286b3d543cbe3 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_fragment.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_fragment.cc
@@ -4,4 +4,15 @@
 
 #include "core/layout/ng/ng_fragment.h"
 
-namespace blink {}  // namespace blink
+#include "core/layout/ng/ng_physical_fragment.h"
+
+namespace blink {
+
+NGMarginStrut NGFragment::MarginStrut() const {
+  // NOTE: Accessing the margin strut ignoring the writing mode here is fine.
+  // Changing the writing mode establishes a new formatting context, for which
+  // a margin strut is never set for a fragment.
+  return toNGPhysicalFragment(physical_fragment_)->MarginStrut();
+}
+
+}  // namespace blink