Add new step graph type to event log visualization tool

webrtc/tools/event_log_visualizer/plot_protobuf.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 20 matching lines @@
       data_set->add_y_values(point.y);
     }
 
     if (series_list_[i].style == BAR_GRAPH) {
       data_set->set_style(webrtc::analytics::ChartStyle::BAR_CHART);
     } else if (series_list_[i].style == LINE_GRAPH) {
       data_set->set_style(webrtc::analytics::ChartStyle::LINE_CHART);
     } else if (series_list_[i].style == LINE_DOT_GRAPH) {
       data_set->set_style(webrtc::analytics::ChartStyle::LINE_CHART);
       data_set->set_highlight_points(true);
+    } else if (series_list_[i].style == LINE_STEP_GRAPH) {
+      data_set->set_style(webrtc::analytics::ChartStyle::LINE_STEP_CHART);
     } else {
       data_set->set_style(webrtc::analytics::ChartStyle::UNDEFINED);
     }
 
     data_set->set_label(series_list_[i].label);
   }
 
   chart->set_xaxis_min(xaxis_min_);
   chart->set_xaxis_max(xaxis_max_);
   chart->set_yaxis_min(yaxis_min_);
@@ skipping 23 matching lines @@
 }
 
 Plot* ProtobufPlotCollection::AppendNewPlot() {
   Plot* plot = new ProtobufPlot();
   plots_.push_back(std::unique_ptr<Plot>(plot));
   return plot;
 }
 
 }  // namespace plotting
 }  // namespace webrtc