Update talk to 50918584.

Together with Stefan's http://review.webrtc.org/1960004/.

R=mallinath@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2048004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4556 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/rtp_rtcp/source/bitrate.h

@@ -42,6 +42,8 @@ class Bitrate {
   // Bitrate last second, updated now.
   uint32_t BitrateNow() const;
 
+  int64_t time_last_rate_update() const;
+
  protected:
   Clock* clock_;