Make NGFragment to own NGPhysicalFragment

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 17 matching lines @@
   NGBlockLayoutAlgorithm(PassRefPtr<const ComputedStyle>, NGBox* first_child);
 
   // Actual layout implementation. Lays out the children in sequence within the
   // constraints given by the NGConstraintSpace. Returns a fragment with the
   // resulting layout information.
   // This function can not be const because for interruptible layout, we have
   // to be able to store state information.
   // Returns true when done; when this function returns false, it has to be
   // called again. The out parameter will only be set when this function
   // returns true. The same constraint space has to be passed each time.
-  bool Layout(const NGConstraintSpace*, NGPhysicalFragment**) override;
+  bool Layout(const NGConstraintSpace&, NGPhysicalFragment**) override;
 
   DEFINE_INLINE_VIRTUAL_TRACE() {
     NGLayoutAlgorithm::trace(visitor);
     visitor->trace(first_child_);
     visitor->trace(builder_);
     visitor->trace(constraint_space_for_children_);
     visitor->trace(current_child_);
   }
 
  private:
@@ skipping 30 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