[LayoutNG] Stack allocate NGLayoutOpportunityIterator.

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

 // 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.
 
 #include "core/layout/ng/ng_block_layout_algorithm.h"
 
 #include "core/layout/ng/ng_absolute_utils.h"
 #include "core/layout/ng/ng_block_break_token.h"
 #include "core/layout/ng/ng_column_mapper.h"
 #include "core/layout/ng/ng_constraint_space.h"
@@ skipping 113 matching lines @@
 // @param margins Margins of the fragment.
 // @return Layout opportunity for the fragment.
 const NGLayoutOpportunity FindLayoutOpportunityForFragment(
     NGConstraintSpace* space,
     const NGFragment& fragment,
     const NGLogicalOffset& origin_point,
     const NGBoxStrut& margins) {
   NGLogicalOffset adjusted_origin_point =
       AdjustToTopEdgeAlignmentRule(*space, origin_point);
 
-  NGLayoutOpportunityIterator* opportunity_iter =
-      space->LayoutOpportunities(adjusted_origin_point);
+  NGLayoutOpportunityIterator opportunity_iter(space, adjusted_origin_point);
   NGLayoutOpportunity opportunity;
-  NGLayoutOpportunity opportunity_candidate = opportunity_iter->Next();
+  NGLayoutOpportunity opportunity_candidate = opportunity_iter.Next();
 
   while (!opportunity_candidate.IsEmpty()) {
     opportunity = opportunity_candidate;
     // Checking opportunity's block size is not necessary as a float cannot be
     // positioned on top of another float inside of the same constraint space.
     auto fragment_inline_size = fragment.InlineSize() + margins.InlineSum();
     if (opportunity.size.inline_size >= fragment_inline_size)
       break;
-    opportunity_candidate = opportunity_iter->Next();
+
+    opportunity_candidate = opportunity_iter.Next();
   }
   return opportunity;
 }
 
 // Calculates the logical offset for opportunity.
 NGLogicalOffset CalculateLogicalOffsetForOpportunity(
     const NGLayoutOpportunity& opportunity,
     const LayoutUnit float_offset,
     const NGBoxStrut& margins,
     const NGLogicalOffset& space_offset) {
@@ skipping 555 matching lines @@
   curr_bfc_offset_.inline_offset += border_and_padding_.inline_start;
   if (ConstraintSpace().IsNewFormattingContext()) {
     curr_bfc_offset_.inline_offset += curr_child_margins_.inline_start;
   }
   space_builder_->SetBfcOffset(curr_bfc_offset_);
 
   return space_builder_->ToConstraintSpace();
 }
 
 }  // namespace blink