Add more out of line copy ctors for complex classes.

components/autofill/core/browser/field_candidates.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 "components/autofill/core/browser/field_candidates.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/logging.h"
 
 namespace autofill {
 
 FieldCandidate::FieldCandidate(ServerFieldType field_type, float field_score)
     : type(field_type), score(field_score) {}
 
 FieldCandidates::FieldCandidates() {}
 
+FieldCandidates::FieldCandidates(const FieldCandidates& other) = default;
+
 FieldCandidates::~FieldCandidates() {}
 
 void FieldCandidates::AddFieldCandidate(ServerFieldType type, float score) {
   field_candidates_.emplace_back(type, score);
 }
 
 // We currently select the type with the biggest sum.
 ServerFieldType FieldCandidates::BestHeuristicType() const {
   if (field_candidates_.empty())
     return UNKNOWN_TYPE;
@@ skipping 12 matching lines @@
   const size_t index = std::distance(type_scores.begin(), best_type_iter);
 
   return static_cast<ServerFieldType>(index);
 }
 
 const std::vector<FieldCandidate>& FieldCandidates::field_candidates() const {
   return field_candidates_;
 }
 
 }  // namespace autofill