Fix bug in calculation of averge queue time in paced sender.

webrtc/modules/pacing/paced_sender.h

Index: webrtc/modules/pacing/paced_sender.h
diff --git a/webrtc/modules/pacing/paced_sender.h b/webrtc/modules/pacing/paced_sender.h
index d1e5ce341d8deb69026a8d7cb15f9b7aacbb42fa..62e794fdbc74929173d75d533e68a9f4b81649c0 100644
--- a/webrtc/modules/pacing/paced_sender.h
+++ b/webrtc/modules/pacing/paced_sender.h
@@ -113,6 +113,10 @@ class PacedSender : public Module, public RtpPacketSender {
   // packets in the queue, given the current size and bitrate, ignoring prio.
   virtual int64_t ExpectedQueueTimeMs() const;
 
+  // Returns the average time since being enqueued, in milliseconds, for all
+  // packets currently in the pacer queue, or 0 if queue is empty.
+  virtual int64_t AverageQueueTimeMs();
+
   // Returns the number of milliseconds until the module want a worker thread
   // to call Process.
   int64_t TimeUntilNextProcess() override;