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

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

Index: third_party/WebKit/Source/core/layout/ng/ng_block_node.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_node.h b/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
index 1893195b39c12a41ffd61704701348af28355f05..942b21234a7a8d784f277e76a0e880dc1f0c3945 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
@@ -34,7 +34,8 @@ class CORE_EXPORT NGBlockNode final : public NGLayoutInputNode {
 
   ~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;