Revert of New method StatsObserver::OnCompleteReports, passing ownership.

webrtc/api/peerconnection.cc

Index: webrtc/api/peerconnection.cc
diff --git a/webrtc/api/peerconnection.cc b/webrtc/api/peerconnection.cc
index 08a8b0d41dceef2d3e3178a86700ff66593e13dc..ebce40ca5eb0cf37d03243663826ea911eda06c3 100644
--- a/webrtc/api/peerconnection.cc
+++ b/webrtc/api/peerconnection.cc
@@ -1441,9 +1441,9 @@
     }
     case MSG_GETSTATS: {
       GetStatsMsg* param = static_cast<GetStatsMsg*>(msg->pdata);
-      std::unique_ptr<StatsReports> reports(new StatsReports);
-      stats_->GetStats(param->track, reports.get());
-      param->observer->OnCompleteReports(std::move(reports));
+      StatsReports reports;
+      stats_->GetStats(param->track, &reports);
+      param->observer->OnComplete(reports);
       delete param;
       break;
     }