Make CounterDirectiveMap a class and implement a Clone() method.

third_party/WebKit/Source/core/style/CounterDirectives.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 14 matching lines @@
 #include "platform/wtf/PtrUtil.h"
 
 namespace blink {
 
 bool operator==(const CounterDirectives& a, const CounterDirectives& b) {
   return a.IsIncrement() == b.IsIncrement() &&
          a.IncrementValue() == b.IncrementValue() &&
          a.IsReset() == b.IsReset() && a.ResetValue() == b.ResetValue();
 }
 
-std::unique_ptr<CounterDirectiveMap> Clone(
-    const CounterDirectiveMap& counter_directives) {
-  std::unique_ptr<CounterDirectiveMap> result =
-      WTF::WrapUnique(new CounterDirectiveMap);
-  *result = counter_directives;
-  return result;
-}
-
 }  // namespace blink