Revert 284958 "Make HistoryDBTask not refcounted, and ensure it'..."

trunk/src/chrome/browser/history/history_service.cc

Index: trunk/src/chrome/browser/history/history_service.cc
===================================================================
--- trunk/src/chrome/browser/history/history_service.cc	(revision 285001)
+++ trunk/src/chrome/browser/history/history_service.cc	(working copy)
@@ -378,7 +378,7 @@
                     urls);
 }
 
-void HistoryService::ScheduleDBTask(scoped_ptr<history::HistoryDBTask> task,
+void HistoryService::ScheduleDBTask(scoped_refptr<history::HistoryDBTask> task,
                                     base::CancelableTaskTracker* tracker) {
   DCHECK(thread_checker_.CalledOnValidThread());
   base::CancelableTaskTracker::IsCanceledCallback is_canceled;
@@ -390,7 +390,7 @@
       FROM_HERE,
       base::Bind(&HistoryBackend::ProcessDBTask,
                  history_backend_.get(),
-                 base::Passed(&task),
+                 task,
                  base::ThreadTaskRunnerHandle::Get(),
                  is_canceled));
 }