Use Opportunity Iterator to position text fragments in NGLineBuilder

third_party/WebKit/Source/core/layout/ng/ng_constraint_space.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_constraint_space.h"
 
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/ng/ng_constraint_space_builder.h"
 #include "core/layout/ng/ng_layout_opportunity_iterator.h"
@@ skipping 117 matching lines @@
 void NGConstraintSpace::AddExclusion(const NGExclusion& exclusion) {
   exclusions_->Add(exclusion);
   // Invalidate the Layout Opportunity Iterator.
   layout_opp_iter_.reset();
 }
 
 NGFragmentationType NGConstraintSpace::BlockFragmentationType() const {
   return static_cast<NGFragmentationType>(block_direction_fragmentation_type_);
 }
 
-NGLayoutOpportunityIterator* NGConstraintSpace::LayoutOpportunityIterator() {
+NGLayoutOpportunityIterator* NGConstraintSpace::LayoutOpportunityIterator(
+    const NGLogicalOffset& iter_offset) {
+  if (layout_opp_iter_ && layout_opp_iter_->Offset() != iter_offset)
+    layout_opp_iter_.reset();
+
   if (!layout_opp_iter_) {
     layout_opp_iter_ =
-        WTF::makeUnique<NGLayoutOpportunityIterator>(this, this->bfc_offset_);
+        WTF::makeUnique<NGLayoutOpportunityIterator>(this, iter_offset);
   }
   return layout_opp_iter_.get();
 }
 
 String NGConstraintSpace::ToString() const {
   return String::format(
       "Offset: %s,%s Size: %sx%s MarginStrut: %s"
       " Clearance: %s",
       bfc_offset_.inline_offset.toString().ascii().data(),
       bfc_offset_.block_offset.toString().ascii().data(),
       AvailableSize().inline_size.toString().ascii().data(),
       AvailableSize().block_size.toString().ascii().data(),
       margin_strut_.ToString().ascii().data(),
       clearance_offset_.has_value()
           ? clearance_offset_.value().toString().ascii().data()
           : "none");
 }
 
 }  // namespace blink