Overlay REMB in total bitrate graphs in visualization tool.

webrtc/tools/event_log_visualizer/plot_base.h

Index: webrtc/tools/event_log_visualizer/plot_base.h
diff --git a/webrtc/tools/event_log_visualizer/plot_base.h b/webrtc/tools/event_log_visualizer/plot_base.h
index afa20beaf8c82f78b5d7b97d6312a09ede95edb5..0abd6befec867b18d71836310605949d7bd58830 100644
--- a/webrtc/tools/event_log_visualizer/plot_base.h
+++ b/webrtc/tools/event_log_visualizer/plot_base.h
@@ -109,6 +109,10 @@ class Plot {
   // Add a new TimeSeries to the plot.
   void AppendTimeSeries(TimeSeries&& time_series);
 
+  // Add a new TimeSeries to the plot if the series contains contains data.
+  // Otherwise, the call has no effect and the timeseries is destroyed.
+  void AppendTimeSeriesIfNotEmpty(TimeSeries&& time_series);
+
  protected:
   float xaxis_min_;
   float xaxis_max_;