Add more out of line copy ctors for complex classes.

components/autofill/core/browser/field_candidates.h

 // 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.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_BROWSER_FIELD_CANDIDATES_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_FIELD_CANDIDATES_H_
 
 #include <unordered_map>
 #include <vector>
 
@@ skipping 11 matching lines @@
   // A non-negative number indicating how sure the type is for this specific
   // candidate. The higher the more confidence.
   float score = 0.0f;
 };
 
 // Each field can be of different types. This class collects all these possible
 // types and determines which type is the most likely.
 class FieldCandidates {
  public:
   FieldCandidates();
+  FieldCandidates(const FieldCandidates& other);
   ~FieldCandidates();
 
   // Includes a possible |type| for a given field.
   //
   // Callers are responsible for the scores they add. FieldCandidates is
   // agnostic to the source of these scores and will select the best candidate
   // based solely on their numeric values. BestHeuristicType() uses |score| to
   // determine the most likely type for this given field. Please see
   // field_candidates.cc for details on how this type is actually chosen.
   void AddFieldCandidate(ServerFieldType type, float score);
@@ skipping 10 matching lines @@
   // Internal storage for all the possible types for a given field.
   std::vector<FieldCandidate> field_candidates_;
 };
 
 // A map from the field's unique name to its possible candidates.
 using FieldCandidatesMap = std::unordered_map<base::string16, FieldCandidates>;
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_FIELD_CANDIDATES_H_