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

third_party/WebKit/Source/core/layout/ng/ng_layout_input_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 NGLayoutInputNode_h
 #define NGLayoutInputNode_h
 
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class LayoutObject;
+class NGBreakToken;
 class NGConstraintSpace;
 class NGLayoutResult;
 
 // Represents the input to a layout algorithm for a given node. The layout
 // engine should use the style, node type to determine which type of layout
 // algorithm to use to produce fragments for this node.
 class CORE_EXPORT NGLayoutInputNode
     : public GarbageCollectedFinalized<NGLayoutInputNode> {
  public:
   enum NGLayoutInputNodeType { kLegacyBlock = 0, kLegacyInline = 1 };
 
   virtual ~NGLayoutInputNode(){};
 
   // Performs layout on this input node, will return the layout result.
-  virtual RefPtr<NGLayoutResult> Layout(NGConstraintSpace*) = 0;
+  virtual RefPtr<NGLayoutResult> Layout(NGConstraintSpace*, NGBreakToken*) = 0;
 
   // Returns the next sibling.
   virtual NGLayoutInputNode* NextSibling() = 0;
 
   // Returns the LayoutObject which is associated with this node.
   virtual LayoutObject* GetLayoutObject() = 0;
 
   NGLayoutInputNodeType Type() const {
     return static_cast<NGLayoutInputNodeType>(type_);
   }
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
  protected:
   explicit NGLayoutInputNode(NGLayoutInputNodeType type) : type_(type) {}
 
  private:
   unsigned type_ : 1;
 };
 
 }  // namespace blink
 
 #endif  // NGLayoutInputNode_h