Add TimeToScrollUpdateSwapBegin2 to UKM

ui/latency/latency_tracker.h

Index: ui/latency/latency_tracker.h
diff --git a/ui/latency/latency_tracker.h b/ui/latency/latency_tracker.h
index 4d0a432a7c847e01b4d16cf81237f94f8877881c..e40b913e1b509c649f8a808256ab6c288daa07b0 100644
--- a/ui/latency/latency_tracker.h
+++ b/ui/latency/latency_tracker.h
@@ -28,6 +28,12 @@ class LatencyTracker {
       const LatencyInfo::LatencyComponent& start_component,
       const LatencyInfo::LatencyComponent& end_component);
 
+  virtual void ReportUkmScrollLatency(
+      const std::string& event_name,
+      const std::string& metric_name,
+      const LatencyInfo::LatencyComponent& start_component,
+      const LatencyInfo::LatencyComponent& end_component);
+
  private:
   void ComputeEndToEndLatencyHistograms(
       const LatencyInfo::LatencyComponent& gpu_swap_begin_component,