Port HistoryService::GetVisibleVisitCountToHost to CancelableTaskTracker

chrome/browser/history/history_backend.h

 // Copyright (c) 2012 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_HISTORY_HISTORY_BACKEND_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 140 matching lines @@
           enumerator);
   void QueryURL(const GURL& url,
                 bool want_visits,
                 QueryURLResult* query_url_result);
   void QueryHistory(const base::string16& text_query,
                     const QueryOptions& options,
                     QueryResults* query_results);
   void QueryRedirectsFrom(const GURL& url, QueryRedirectsResult* result);
   void QueryRedirectsTo(const GURL& url, QueryRedirectsResult* result);
 
-  void GetVisibleVisitCountToHost(
-      scoped_refptr<GetVisibleVisitCountToHostRequest> request,
-      const GURL& url);
+  void GetVisibleVisitCountToHost(const GURL& url,
+                                  VisibleVisitCountToHostResult* result);
 
   // TODO(Nik): remove. Use QueryMostVisitedURLs instead.
   void QueryTopURLsAndRedirects(
       scoped_refptr<QueryTopURLsAndRedirectsRequest> request,
       int result_count);
 
   // Request the |result_count| most visited URLs and the chain of
   // redirects leading to each of these URLs. |days_back| is the
   // number of days of history to use. Used by TopSites.
   void QueryMostVisitedURLs(
@@ skipping 689 matching lines @@
 
   // Listens for the system being under memory pressure.
   scoped_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryBackend);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_