Implement qpSum stat for video send ssrc stats.

webrtc/video/send_statistics_proxy_unittest.cc

Index: webrtc/video/send_statistics_proxy_unittest.cc
diff --git a/webrtc/video/send_statistics_proxy_unittest.cc b/webrtc/video/send_statistics_proxy_unittest.cc
index cb3bde442647856fab6cea7b41e575148105b45e..0e29533243b1df453bead155fe2ae65474eec3d4 100644
--- a/webrtc/video/send_statistics_proxy_unittest.cc
+++ b/webrtc/video/send_statistics_proxy_unittest.cc
@@ -311,6 +311,18 @@ TEST_F(SendStatisticsProxyTest, OnSendEncodedImageIncreasesFramesEncoded) {
   }
 }
 
+TEST_F(SendStatisticsProxyTest, OnSendEncodedImageIncreasesQpSum) {
+  EncodedImage encoded_image;
+  CodecSpecificInfo codec_info;
+  EXPECT_EQ(0u, statistics_proxy_->GetStats().qp_sum);
+  encoded_image.qp_ = 3;
+  statistics_proxy_->OnSendEncodedImage(encoded_image, &codec_info);
+  EXPECT_EQ(3u, statistics_proxy_->GetStats().qp_sum);
+  encoded_image.qp_ = 127;
+  statistics_proxy_->OnSendEncodedImage(encoded_image, &codec_info);
+  EXPECT_EQ(130u, statistics_proxy_->GetStats().qp_sum);

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

Can you add an unittest that chekcs that if codec is not VP8, the qp_sum will
start at -1 and remain at -1?

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

Since QP sum is an unsigned type, it cannot be -1. I made it rtc::Optional
instead. Done.

+}
+
 TEST_F(SendStatisticsProxyTest, SwitchContentTypeUpdatesHistograms) {
   const int kWidth = 640;
   const int kHeight = 480;