[LayoutNG] Switch NGConstraintSpace to being RefCounted.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.h b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.h
index 3c4aa9317466098e5e86cad2952bbdc70416d160..215cbc68c4d96174e66df45cd33701032d5290ef 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.h
@@ -43,7 +43,7 @@ class CORE_EXPORT NGBlockLayoutAlgorithm : public NGLayoutAlgorithm {
                               const NGConstraintSpace& space);
 
   // Creates a new constraint space for the current child.
-  NGConstraintSpace* CreateConstraintSpaceForChild(NGLayoutInputNode*);
+  RefPtr<NGConstraintSpace> CreateConstraintSpaceForChild(NGLayoutInputNode*);
   void FinishChildLayout(NGLayoutInputNode*,
                          NGConstraintSpace*,
                          RefPtr<NGLayoutResult>);
@@ -71,13 +71,14 @@ class CORE_EXPORT NGBlockLayoutAlgorithm : public NGLayoutAlgorithm {
   }
 
   const NGConstraintSpace& ConstraintSpace() const {
+    DCHECK(constraint_space_);
     return *constraint_space_;
   }
 
   const ComputedStyle& Style() const { return node_->Style(); }
 
   Persistent<NGBlockNode> node_;
-  Persistent<NGConstraintSpace> constraint_space_;
+  NGConstraintSpace* constraint_space_;

[ikilpatrick, 2017/03/02 17:20:15]

Just a pointer as STACK_ALLOCATED(). Going to change the BreakToken patch to
match this.

 
   // The break token from which we are currently resuming layout.
   Persistent<NGBlockBreakToken> break_token_;