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

chrome/browser/history/history_service.h

Index: chrome/browser/history/history_service.h
diff --git a/chrome/browser/history/history_service.h b/chrome/browser/history/history_service.h
index 216c4517f96cdb7513f5a7d0031fdfe51d6916fb..2e10bbe5f4d6a20d6f143b13199392261e978b93 100644
--- a/chrome/browser/history/history_service.h
+++ b/chrome/browser/history/history_service.h
@@ -443,8 +443,8 @@ class HistoryService : public CancelableRequestProvider,
   // 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.