[LayoutNG] Allow block-flow layout to be fragmented using new approach.

third_party/WebKit/Source/core/layout/ng/ng_block_node.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 NGBlockNode_h
 #define NGBlockNode_h
 
 #include "core/CoreExport.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/ng/ng_layout_input_node.h"
@@ skipping 16 matching lines @@
   friend NGLayoutInputNode;
 
  public:
   explicit NGBlockNode(LayoutObject*);
 
   // TODO(layout-ng): make it private and declare a friend class to use in tests
   explicit NGBlockNode(ComputedStyle*);
 
   ~NGBlockNode() override;
 
-  RefPtr<NGLayoutResult> Layout(NGConstraintSpace* constraint_space) override;
+  RefPtr<NGLayoutResult> Layout(NGConstraintSpace* constraint_space,
+                                NGBreakToken* break_token) override;

[Gleb Lanbin, 2017/02/24 21:51:28]

NGBreakToken* break_token = nullptr)

[ikilpatrick, 2017/02/25 00:57:22]

Done. Yeah I flipped back and forth on this a little. Other the other hand it
forces callers to be explicit, but probably fine.

   NGLayoutInputNode* NextSibling() override;
   LayoutObject* GetLayoutObject() override;
 
   // Computes the value of min-content and max-content for this box.
   // If the underlying layout algorithm's ComputeMinAndMaxContentSizes returns
   // no value, this function will synthesize these sizes using Layout with
   // special constraint spaces -- infinite available size for max content, zero
   // available size for min content, and percentage resolution size zero for
   // both.
   MinAndMaxContentSizes ComputeMinAndMaxContentSizes();
@@ skipping 45 matching lines @@
 
 DEFINE_TYPE_CASTS(NGBlockNode,
                   NGLayoutInputNode,
                   node,
                   node->Type() == NGLayoutInputNode::kLegacyBlock,
                   node.Type() == NGLayoutInputNode::kLegacyBlock);
 
 }  // namespace blink
 
 #endif  // NGBlockNode