Add delay metric (includes network delay (rtt/2) + jitter delay + decode time +

webrtc/video_engine/vie_channel.h

Index: webrtc/video_engine/vie_channel.h
diff --git a/webrtc/video_engine/vie_channel.h b/webrtc/video_engine/vie_channel.h
index fc015926fa46d5f23744b41c41aac3583bd0a232..d2691043b9d18d124c6e26907e534e4e28a5085c 100644
--- a/webrtc/video_engine/vie_channel.h
+++ b/webrtc/video_engine/vie_channel.h
@@ -443,6 +443,7 @@ class ViEChannel : public VCMFrameTypeCallback,
 
   int64_t time_of_first_rtt_ms_ GUARDED_BY(crit_);
   int64_t rtt_sum_ms_ GUARDED_BY(crit_);
+  int64_t last_rtt_ms_ GUARDED_BY(crit_);
   size_t num_rtts_ GUARDED_BY(crit_);
 
   // RtpRtcp modules, declared last as they use other members on construction.