Move chart proto for event_log_visualizer.

Bug: None
Change-Id: I7bca9002f208ac0bafc2d2d399978a289209496f
Reviewed-on: https://webrtc-review.googlesource.com/c/113815
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25963}

rtc_tools/event_log_visualizer/proto/chart.proto

@@ -0,0 +1,29 @@
+syntax = "proto3";
+// Describes a chart generated from WebRTC event log data.
+option optimize_for = LITE_RUNTIME;
+package webrtc.analytics;
+
+import "chart_enums.proto";
+
+message DataSet {
+  repeated float x_values = 1;
+  repeated float y_values = 2;
+  string label = 3;
+  ChartStyle.Type style = 4;
+  bool highlight_points = 5;
+}
+
+message Chart {
+  repeated DataSet data_sets = 1;
+  float xaxis_min = 2;
+  float xaxis_max = 3;
+  string xaxis_label = 4;
+  float yaxis_min = 5;
+  float yaxis_max = 6;
+  string yaxis_label = 7;
+  string title = 8;
+}
+
+message ChartCollection {
+  repeated Chart charts = 1;
+}

rtc_tools/event_log_visualizer/proto/chart_enums.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+// Contains enums used as part of chart.proto
+package webrtc.analytics;
+
+message ChartStyle {
+  enum Type {
+    UNDEFINED = 0;
+    LINE_CHART = 1;
+    BAR_CHART = 2;
+    LINE_STEP_CHART = 3;
+    SCATTER_CHART = 4;
+  };
+};