Make HistoryDBTask not refcounted, and ensure it's destroyed on its origin thread.

chrome/browser/history/history_service.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_SERVICE_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_SERVICE_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 425 matching lines @@
                                     const base::string16& term);
 
   // Bookmarks -----------------------------------------------------------------
 
   // Notification that a URL is no longer bookmarked.
   void URLsNoLongerBookmarked(const std::set<GURL>& urls);
 
   // Generic Stuff -------------------------------------------------------------
 
   // Schedules a HistoryDBTask for running on the history backend thread. See
-  // HistoryDBTask for details on what this does.
-  virtual void ScheduleDBTask(scoped_refptr<history::HistoryDBTask> task,
+  // HistoryDBTask for details on what this does. Takes ownership of |task|.
+  virtual void ScheduleDBTask(history::HistoryDBTask* task,

[sky, 2014/07/14 20:27:44]

Make take a scoped_ptr.

[Bernhard Bauer, 2014/07/15 10:17:24]

Done.

                               base::CancelableTaskTracker* tracker);
 
   // Adds or removes observers for the VisitDatabase.
   void AddVisitDatabaseObserver(history::VisitDatabaseObserver* observer);
   void RemoveVisitDatabaseObserver(history::VisitDatabaseObserver* observer);
 
   void NotifyVisitDBObserversOnAddVisit(const history::BriefVisitInfo& info);
 
   // Testing -------------------------------------------------------------------
 
@@ skipping 516 matching lines @@
   scoped_ptr<history::InMemoryURLIndex> in_memory_url_index_;
 
   ObserverList<history::VisitDatabaseObserver> visit_database_observers_;
 
   history::DeleteDirectiveHandler delete_directive_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_SERVICE_H_