Pass label and plot style to the TimeSeries' constructor.

webrtc/tools/event_log_visualizer/plot_base.cc

Index: webrtc/tools/event_log_visualizer/plot_base.cc
diff --git a/webrtc/tools/event_log_visualizer/plot_base.cc b/webrtc/tools/event_log_visualizer/plot_base.cc
index f27fcd6b84ff2fe6412dbf03b4b35065a6d39bbb..baee3dfeee3cd0708bd8e490a791b0560802fa33 100644
--- a/webrtc/tools/event_log_visualizer/plot_base.cc
+++ b/webrtc/tools/event_log_visualizer/plot_base.cc
@@ -71,5 +71,15 @@ void Plot::SetTitle(std::string title) {
   title_ = title;
 }
 
+TimeSeries* Plot::AddTimeSeries(const char* label, PlotStyle style) {
+  series_list_.emplace_back(label, style);
+  return &series_list_.back();
+}
+
+TimeSeries* Plot::AddTimeSeries(const std::string& label, PlotStyle style) {
+  series_list_.emplace_back(label, style);
+  return &series_list_.back();
+}
+
 }  // namespace plotting
 }  // namespace webrtc