Add histogram stats for send delay for a sent video stream.

webrtc/call/rtc_event_log_unittest.cc

Index: webrtc/call/rtc_event_log_unittest.cc
diff --git a/webrtc/call/rtc_event_log_unittest.cc b/webrtc/call/rtc_event_log_unittest.cc
index e3104591d9ab55847f424d97c8dae5451dc20f7f..81cc9a075ce2aaf87e126b9770c8c07c047597bc 100644
--- a/webrtc/call/rtc_event_log_unittest.cc
+++ b/webrtc/call/rtc_event_log_unittest.cc
@@ -314,7 +314,8 @@ size_t GenerateRtpPacket(uint32_t extensions_bitvector,
                        nullptr,   // BitrateStatisticsObserver*
                        nullptr,   // FrameCountObserver*
                        nullptr,   // SendSideDelayObserver*
-                       nullptr);  // RtcEventLog*
+                       nullptr,   // RtcEventLog*
+                       nullptr);  // SendPacketObserver*
 
   std::vector<uint32_t> csrcs;
   for (unsigned i = 0; i < csrcs_count; i++) {