LatencyInfo trace_id_ no longer dependent on sequence_number.

ui/latency/mojo/latency_info_struct_traits.cc

Index: ui/latency/mojo/latency_info_struct_traits.cc
diff --git a/ui/latency/mojo/latency_info_struct_traits.cc b/ui/latency/mojo/latency_info_struct_traits.cc
index 12daf3348620a48e7217aaaebb8a53d61b811828..8e27b541be028b54eb273352ef12b6a835d28eea 100644
--- a/ui/latency/mojo/latency_info_struct_traits.cc
+++ b/ui/latency/mojo/latency_info_struct_traits.cc
@@ -290,6 +290,12 @@ bool StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo>::coalesced(
   return info.coalesced();
 }
 
+// static
+bool StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo>::began(
+    const ui::LatencyInfo& info) {
+  return info.began();
+}
+
 // static
 bool StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo>::terminated(
     const ui::LatencyInfo& info) {
@@ -325,6 +331,7 @@ bool StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo>::Read(
 
   out->trace_id_ = data.trace_id();
   out->coalesced_ = data.coalesced();
+  out->began_ = data.began();
   out->terminated_ = data.terminated();
   out->source_event_type_ = MojoSourceEventTypeToUI(data.source_event_type());
   return true;