Delay based logging.

BUG=none

Review-Url: https://codereview.webrtc.org/2808833002
Cr-Commit-Position: refs/heads/master@{#17641}

webrtc/tools/event_log_visualizer/plot_python.cc

@@ -78,7 +78,7 @@ void PythonPlot::Draw() {
       } else if (series_list_[i].style == DOT_GRAPH) {
         printf(
             "plt.plot(x%zu, y%zu, color=rgb_colors[%zu], label=\'%s\', "
-            "marker='.', ls=' ')\n",
+            "marker='o', ls=' ')\n",
             i, i, i, series_list_[i].label.c_str());
       } else {
         printf("raise Exception(\"Unknown graph type\")\n");