Add QP sum stats for received streams.

webrtc/modules/video_coding/include/video_coding_defines.h

Index: webrtc/modules/video_coding/include/video_coding_defines.h
diff --git a/webrtc/modules/video_coding/include/video_coding_defines.h b/webrtc/modules/video_coding/include/video_coding_defines.h
index 122ddc6315c5b85a3a5ac5c7cd4654ecb6cc6880..19b469984c4ada910eb0fb81d3cc1cddaf9ad668 100644
--- a/webrtc/modules/video_coding/include/video_coding_defines.h
+++ b/webrtc/modules/video_coding/include/video_coding_defines.h
@@ -63,7 +63,8 @@ struct VCMFrameCount {
 // rendered.
 class VCMReceiveCallback {
  public:
-  virtual int32_t FrameToRender(VideoFrame& videoFrame) = 0;  // NOLINT
+  virtual int32_t FrameToRender(VideoFrame& videoFrame,
+                                rtc::Optional<uint8_t> qp) = 0;  // NOLINT
   virtual int32_t ReceivedDecodedReferenceFrame(const uint64_t pictureId) {
     return -1;
   }