Add QP sum stats for received streams.

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 f72d7ae86c49403eb7f73cc6b23c43b5a44639a2..f83266f41e07a8ab2815725cee0db162cf7f21dd 100644
--- a/webrtc/media/engine/webrtcvideoengine2_unittest.cc
+++ b/webrtc/media/engine/webrtcvideoengine2_unittest.cc
@@ -3325,6 +3325,7 @@ TEST_F(WebRtcVideoChannel2Test, GetStatsTranslatesDecodeStatsCorrectly) {
   stats.frame_counts.delta_frames = 12;
   stats.frames_rendered = 13;
   stats.frames_decoded = 14;
+  stats.qp_sum = rtc::Optional<uint64_t>(15);
   stream->SetStats(stats);
 
   cricket::VideoMediaInfo info;
@@ -3344,6 +3345,7 @@ TEST_F(WebRtcVideoChannel2Test, GetStatsTranslatesDecodeStatsCorrectly) {
             info.receivers[0].frames_received);
   EXPECT_EQ(stats.frames_rendered, info.receivers[0].frames_rendered);
   EXPECT_EQ(stats.frames_decoded, info.receivers[0].frames_decoded);
+  EXPECT_EQ(stats.qp_sum, info.receivers[0].qp_sum);

[hta-webrtc, 2017/01/26 12:54:52]

Will this comparision be correct? If stats.qp_sum is an rtc::Optional, checking
it will return a flag on whether it's present or not, right?

So it's checking whether both are present, not whether both have the same value.

 }
 
 TEST_F(WebRtcVideoChannel2Test, GetStatsTranslatesReceivePacketStatsCorrectly) {