Implement qpSum stat for video send ssrc stats.

webrtc/api/statscollector_unittest.cc

Index: webrtc/api/statscollector_unittest.cc
diff --git a/webrtc/api/statscollector_unittest.cc b/webrtc/api/statscollector_unittest.cc
index 782926bcee734b1ad868f4043d6fb14cc0b1cb9c..f0370dc0352e4c997bb45522173dcaae0f917ca7 100644
--- a/webrtc/api/statscollector_unittest.cc
+++ b/webrtc/api/statscollector_unittest.cc
@@ -1921,6 +1921,7 @@ TEST_F(StatsCollectorTest, VerifyVideoSendSsrcStats) {
   // Construct a stats value to read.
   video_sender_info.add_ssrc(1234);
   video_sender_info.frames_encoded = 10;
+  video_sender_info.qp_sum = 11;

[hta-webrtc, 2016/10/21 09:13:12]

This is a clash with the other CL (frames_decoded stat). Pick a different
number?

[sakal, 2016/10/21 14:17:26]

Does it really matter since it is in a different test?

   stats_read.senders.push_back(video_sender_info);
 
   EXPECT_CALL(session_, video_channel()).WillRepeatedly(Return(&video_channel));
@@ -1932,6 +1933,8 @@ TEST_F(StatsCollectorTest, VerifyVideoSendSsrcStats) {
   EXPECT_EQ(rtc::ToString(video_sender_info.frames_encoded),
             ExtractSsrcStatsValue(reports,
                                   StatsReport::kStatsValueNameFramesEncoded));
+  EXPECT_EQ(rtc::ToString(video_sender_info.qp_sum),
+            ExtractSsrcStatsValue(reports, StatsReport::kStatsValueNameQpSum));

[hta-webrtc, 2016/10/21 09:13:12]

Can you add a test that verifies that when qp_sum is -1, the field is NOT
generated?

[sakal, 2016/10/21 14:17:26]

Done.

 }
 
 // This test verifies that stats are correctly set in video receive ssrc stats.