[LayoutNG] Stack allocate NGLayoutOpportunityIterator.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h b/third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h
index 09f55f89cbe16df620ebbbcecee201f4ef442c2f..35622c7f22cb78b3cf70c42f8ad3ff528a5ca3f6 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h
@@ -16,7 +16,6 @@ namespace blink {
 
 class LayoutBox;
 class NGBoxFragment;
-class NGLayoutOpportunityIterator;
 
 enum NGFragmentationType {
   kFragmentNone,
@@ -109,9 +108,6 @@ class CORE_EXPORT NGConstraintSpace final
   // size, or add an exclusion.
   void Subtract(const NGBoxFragment*);
 
-  NGLayoutOpportunityIterator* LayoutOpportunities(
-      const WTF::Optional<NGLogicalOffset>& opt_origin_point = WTF::nullopt);
-
   NGMarginStrut MarginStrut() const { return margin_strut_; }
 
   NGLogicalOffset BfcOffset() const { return bfc_offset_; }