Change HistoryService::ScheduleAutocomplete interface

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 141 matching lines @@
   void AddPage(const HistoryAddPageArgs& request);
   virtual void SetPageTitle(const GURL& url, const base::string16& title);
   void AddPageNoVisitForBookmark(const GURL& url, const base::string16& title);
   void UpdateWithPageEndTime(ContextID context_id,
                              int32 page_id,
                              const GURL& url,
                              base::Time end_ts);
 
   // Querying ------------------------------------------------------------------
 
-  // ScheduleAutocomplete() never frees |provider| (which is globally live).
-  // It passes |params| on to the autocomplete system which will eventually
-  // free it.
-  void ScheduleAutocomplete(HistoryURLProvider* provider,
-                            HistoryURLProviderParams* params);
+  // Run the |callback| on the History thread.
+  // history_url_provider.h has the temporal ordering for
+  // the call sequence.
+  // |callback| should handle the NULL database case.
+  void ScheduleAutocomplete(const base::Callback<
+      void(history::HistoryBackend*, history::URLDatabase*)>& callback);
 
   void IterateURLs(
       const scoped_refptr<visitedlink::VisitedLinkDelegate::URLEnumerator>&
           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);
@@ skipping 676 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_