Move counters for passwords, history and autofill to components

chrome/browser/browsing_data/downloads_counter.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 CHROME_BROWSER_BROWSING_DATA_DOWNLOADS_COUNTER_H_
 #define CHROME_BROWSER_BROWSING_DATA_DOWNLOADS_COUNTER_H_
 
 #include "components/browsing_data/core/counters/browsing_data_counter.h"
 
 class Profile;
 
 // A BrowsingDataCounter that counts the number of downloads as seen on the
 // chrome://downloads page.
 class DownloadsCounter : public browsing_data::BrowsingDataCounter {
  public:
   explicit DownloadsCounter(Profile* profile);
   ~DownloadsCounter() override;
 
+  const char* GetPrefName() const override;
+
  private:
   // BrowsingDataRemover implementation.
   void Count() override;
 
-  const std::string pref_name_;
-
   Profile* profile_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadsCounter);
 };
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_DOWNLOADS_COUNTER_H_