Implement qpSum stat for video send ssrc stats.

webrtc/media/engine/webrtcvideoengine2_unittest.cc

Index: webrtc/media/engine/webrtcvideoengine2_unittest.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2_unittest.cc b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
index a80ae9db60d928c92a543982446b85a974db9eaf..3b4a868afc982253e9bb48d2b0ddf3aab16340d1 100644
--- a/webrtc/media/engine/webrtcvideoengine2_unittest.cc
+++ b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
@@ -2905,6 +2905,17 @@ TEST_F(WebRtcVideoChannel2Test, GetStatsReportsFramesEncoded) {
   EXPECT_EQ(stats.frames_encoded, info.senders[0].frames_encoded);
 }
 
+TEST_F(WebRtcVideoChannel2Test, GetStatsReportsQpSum) {
+  FakeVideoSendStream* stream = AddSendStream();
+  webrtc::VideoSendStream::Stats stats;
+  stats.qp_sum = rtc::Optional<uint64_t>(13);
+  stream->SetStats(stats);
+
+  cricket::VideoMediaInfo info;
+  ASSERT_TRUE(channel_->GetStats(&info));
+  EXPECT_EQ(stats.qp_sum, info.senders[0].qp_sum);
+}
+
 TEST_F(WebRtcVideoChannel2Test, GetStatsReportsUpperResolution) {
   FakeVideoSendStream* stream = AddSendStream();
   webrtc::VideoSendStream::Stats stats;