Fix incorrectly calculated content_size for fragments that create new FC

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

 // 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.
 
 #ifndef NGBlockLayoutAlgorithm_h
 #define NGBlockLayoutAlgorithm_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_box.h"
 #include "core/layout/ng/ng_fragment_builder.h"
@@ skipping 35 matching lines @@
   }
 
  private:
   // Computes collapsed margins for 2 adjoining blocks and updates the resultant
   // fragment's MarginStrut if needed.
   // See https://www.w3.org/TR/CSS2/box.html#collapsing-margins
   //
   // @param space Constraint space for the block.
   // @param child_margins Margins information for the current child.
   // @param fragment Current child's fragment.
-  // @return Margin block start based on collapsed margins result.
-  LayoutUnit CollapseMargins(const NGConstraintSpace& space,
+  // @return NGBoxStrut with margins block start/end.
+  NGBoxStrut CollapseMargins(const NGConstraintSpace& space,
                              const NGBoxStrut& child_margins,
                              const NGFragment& fragment);
 
   // Updates block-{start|end} of the currently constructed fragment.
   //
   // This method is supposed to be called on every child but it only updates
   // the block-start once (on the first non-zero height child fragment) and
   // keeps updating block-end (on every non-zero height child).
   void UpdateMarginStrut(const NGMarginStrut& from);
 
@@ skipping 11 matching lines @@
   // MarginStrut for the previous child.
   NGMarginStrut prev_child_margin_strut_;
   // Whether the block-start was set for the currently built
   // fragment's margin strut.
   bool is_fragment_margin_strut_block_start_updated_ : 1;
 };
 
 }  // namespace blink
 
 #endif  // NGBlockLayoutAlgorithm_h