Pass label and plot style to the TimeSeries' constructor.

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 e2bec2df78cb75b842cab7863727a1f46ebf2bd4..0c0ebc0b7c87593ee9e3559d13ff595122e6d145 100644
--- a/webrtc/tools/event_log_visualizer/plot_base.h
+++ b/webrtc/tools/event_log_visualizer/plot_base.h
@@ -28,6 +28,10 @@ struct TimeSeriesPoint {
 
 struct TimeSeries {
   TimeSeries() = default;
+  TimeSeries(const char* label, PlotStyle style)
+      : label(label), style(style), points() {}
+  TimeSeries(const std::string& label, PlotStyle style)
+      : label(label), style(style), points() {}
   TimeSeries(TimeSeries&& other)
       : label(std::move(other.label)),
         style(other.style),
@@ -97,6 +101,10 @@ class Plot {
   // Sets the title of the plot.
   void SetTitle(std::string title);
 
+  // Add a new TimeSeries to the plot.
+  TimeSeries* AddTimeSeries(const char* label, PlotStyle style);
+  TimeSeries* AddTimeSeries(const std::string& label, PlotStyle style);
+
   std::vector<TimeSeries> series_list_;
 
  protected: