Reland of Add QP sum stats for received streams.

webrtc/pc/statscollector_unittest.cc

Index: webrtc/pc/statscollector_unittest.cc
diff --git a/webrtc/pc/statscollector_unittest.cc b/webrtc/pc/statscollector_unittest.cc
index e89da1c8aefc5a727afa4d8c82f4992cf3305a7c..1bb6d1de4c19e38aa963c4b530958f045ef50f3a 100644
--- a/webrtc/pc/statscollector_unittest.cc
+++ b/webrtc/pc/statscollector_unittest.cc
@@ -2018,6 +2018,7 @@
   // Construct a stats value to read.
   video_receiver_info.add_ssrc(1234);
   video_receiver_info.frames_decoded = 10;
+  video_receiver_info.qp_sum = rtc::Optional<uint64_t>(11);
   stats_read.receivers.push_back(video_receiver_info);
 
   EXPECT_CALL(session_, video_channel()).WillRepeatedly(Return(&video_channel));
@@ -2029,6 +2030,8 @@
   EXPECT_EQ(rtc::ToString(video_receiver_info.frames_decoded),
             ExtractSsrcStatsValue(reports,
                                   StatsReport::kStatsValueNameFramesDecoded));
+  EXPECT_EQ(rtc::ToString(*video_receiver_info.qp_sum),
+            ExtractSsrcStatsValue(reports, StatsReport::kStatsValueNameQpSum));
 }
 
 }  // namespace webrtc