Add new step graph type to event log visualization tool

webrtc/tools/event_log_visualizer/analyzer.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 535 matching lines @@
     StreamId stream_id = kv.first;
     const std::vector<T>& packet_stream = kv.second;
     // Filter on direction and SSRC.
     if (stream_id.GetDirection() != desired_direction ||
         !MatchingSsrc(stream_id.GetSsrc(), desired_ssrc_)) {
       continue;
     }
 
     TimeSeries time_series;
     time_series.label = label_prefix + " " + GetStreamName(stream_id);
-    time_series.style = LINE_GRAPH;
+    time_series.style = LINE_STEP_GRAPH;
 
     for (size_t i = 0; i < packet_stream.size(); i++) {
       float x = static_cast<float>(packet_stream[i].timestamp - begin_time_) /
                 1000000;
-      time_series.points.emplace_back(x, i);
       time_series.points.emplace_back(x, i + 1);
     }
 
     plot->series_list_.push_back(std::move(time_series));
   }
 }
 
 void EventLogAnalyzer::CreateAccumulatedPacketsGraph(
     PacketDirection desired_direction,
     Plot* plot) {
@@ skipping 298 matching lines @@
   // Overlay the send-side bandwidth estimate over the outgoing bitrate.
   if (desired_direction == kOutgoingPacket) {
     plot->series_list_.push_back(TimeSeries());
     for (auto& bwe_update : bwe_loss_updates_) {
       float x =
           static_cast<float>(bwe_update.timestamp - begin_time_) / 1000000;
       float y = static_cast<float>(bwe_update.new_bitrate) / 1000;
       plot->series_list_.back().points.emplace_back(x, y);
     }
     plot->series_list_.back().label = "Loss-based estimate";
-    plot->series_list_.back().style = LINE_GRAPH;
+    plot->series_list_.back().style = LINE_STEP_GRAPH;
   }
-  plot->series_list_.back().style = LINE_GRAPH;
   plot->SetXAxis(0, call_duration_s_, "Time (s)", kLeftMargin, kRightMargin);
   plot->SetSuggestedYAxis(0, 1, "Bitrate (kbps)", kBottomMargin, kTopMargin);
   if (desired_direction == webrtc::PacketDirection::kIncomingPacket) {
     plot->SetTitle("Incoming RTP bitrate");
   } else if (desired_direction == webrtc::PacketDirection::kOutgoingPacket) {
     plot->SetTitle("Outgoing RTP bitrate");
   }
 }
 
 // For each SSRC, plot the bandwidth used by that stream.
@@ skipping 297 matching lines @@
         int64_t capture_ms = packet.header.timestamp / 90.0;
         int64_t arrival_ms = packet.timestamp / 1000.0;
         timestamps.push_back(std::make_pair(capture_ms, arrival_ms));
       }
     }
   }
   return timestamps;
 }
 }  // namespace plotting
 }  // namespace webrtc