WIP: Plumbing input event latency reporting through Mus GPU.

ui/events/mojo/latency_info_struct_traits.h

Index: ui/events/mojo/latency_info_struct_traits.h
diff --git a/ui/events/mojo/latency_info_struct_traits.h b/ui/events/mojo/latency_info_struct_traits.h
index a46905cb5f9c88225cd0b41c79d836c775939fde..62205308b05499bd6b9c134c4ffd373e5b904ba9 100644
--- a/ui/events/mojo/latency_info_struct_traits.h
+++ b/ui/events/mojo/latency_info_struct_traits.h
@@ -46,6 +46,10 @@ struct StructTraits<ui::mojom::LatencyComponentDataView,
       const ui::LatencyInfo::LatencyComponent& component);
   static uint32_t event_count(
       const ui::LatencyInfo::LatencyComponent& component);
+  static base::TimeTicks first_event_time(
+      const ui::LatencyInfo::LatencyComponent& component);
+  static base::TimeTicks last_event_time(
+      const ui::LatencyInfo::LatencyComponent& component);
   static bool Read(ui::mojom::LatencyComponentDataView data,
                    ui::LatencyInfo::LatencyComponent* out);
 };