Resolve ApplyAutoMargins's TODO in NGBlockLayoutAlgorithm.

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ng/ng_length_utils.h"
 
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_fragment.h"
 #include "core/style/ComputedStyle.h"
 #include "platform/LayoutUnit.h"
@@ skipping 269 matching lines @@
                           LengthResolveType::MarginBorderPaddingSize);
   padding.block_end =
       ResolveInlineLength(constraintSpace, style, style.paddingAfter(),
                           LengthResolveType::MarginBorderPaddingSize);
   return padding;
 }
 
 void ApplyAutoMargins(const NGConstraintSpace& constraint_space,
                       const ComputedStyle& style,
                       const NGFragment& fragment,
-                      NGBoxStrut& margins) {
-  const LayoutUnit used_space = fragment.InlineSize() + margins.InlineSum();
+                      NGBoxStrut* margins) {
+  DCHECK(margins) << "Margins cannot be NULL here";
+  const LayoutUnit used_space = fragment.InlineSize() + margins->InlineSum();
   const LayoutUnit available_space =
       constraint_space.ContainerSize().inline_size - used_space;
   if (available_space < LayoutUnit())
     return;
   if (style.marginStart().isAuto() && style.marginEnd().isAuto()) {
-    margins.inline_start = available_space / 2;
-    margins.inline_end = available_space - margins.inline_start;
+    margins->inline_start = available_space / 2;
+    margins->inline_end = available_space - margins->inline_start;
   } else if (style.marginStart().isAuto()) {
-    margins.inline_start = available_space;
+    margins->inline_start = available_space;
   } else if (style.marginEnd().isAuto()) {
-    margins.inline_end = available_space;
+    margins->inline_end = available_space;
   }
 }
 
 }  // namespace blink