Add QP stats for sent video streams to StatsReport.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc

Index: webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
index 605b4d16fe1a1b4d279ecf7de6259ea11bb0f1c3..98a635ab3911a7a51dfb10d301c1de2da2e8d281 100644
--- a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
@@ -1031,6 +1031,10 @@ int VP8EncoderImpl::GetEncodedPartitions(const VideoFrame& input_image,
         // Report once per frame (lowest stream always sent).
         encoded_images_[encoder_idx].adapt_reason_.bw_resolutions_disabled =
             (stream_idx == 0) ? bw_resolutions_disabled : -1;
+        int qp_128 = -1;
+        vpx_codec_control(
+            &encoders_[encoder_idx], VP8E_GET_LAST_QUANTIZER, &qp_128);
+        encoded_images_[encoder_idx].qp_ = qp_128;
         encoded_complete_callback_->Encoded(encoded_images_[encoder_idx],
                                             &codec_specific, &frag_info);
       } else if (codec_.mode == kScreensharing) {