Replace profile statistics preference count with AutofillCounter

chrome/browser/profiles/profile_statistics.h

 // Copyright 2015 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 CHROME_BROWSER_PROFILES_PROFILE_STATISTICS_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_STATISTICS_H_
 
+#include <memory>
 #include <string>
 
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/profiles/profile_statistics_common.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 class Profile;
 class ProfileStatisticsAggregator;
 
 // Instances of ProfileStatistics should be created directly. Use
 // ProfileStatisticsFactory instead.
 class ProfileStatistics : public KeyedService {
  public:
   // Profile Statistics --------------------------------------------------------
 
   // This function collects statistical information about |profile|, also
   // returns the information via |callback| if |callback| is not null.
-  // Currently bookmarks, history, logins and preferences are counted. The
+  // Currently bookmarks, history, logins and autofill forms are counted. The
   // callback function will probably be called more than once, so binding
   // parameters with bind::Passed() is prohibited.
   void GatherStatistics(const profiles::ProfileStatisticsCallback& callback);
 
  private:
   friend class ProfileStatisticsFactory;
 
   explicit ProfileStatistics(Profile* profile);
   ~ProfileStatistics() override;
   void DeregisterAggregator();
 
   Profile* profile_;
-  scoped_refptr<ProfileStatisticsAggregator> aggregator_;
+  std::unique_ptr<ProfileStatisticsAggregator> aggregator_;
   base::WeakPtrFactory<ProfileStatistics> weak_ptr_factory_;
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_STATISTICS_H_