Histogram for recording actual log upload interval added.

components/metrics/metrics_reporting_scheduler.h

Index: components/metrics/metrics_reporting_scheduler.h
diff --git a/components/metrics/metrics_reporting_scheduler.h b/components/metrics/metrics_reporting_scheduler.h
index 6aa1f3914bc91bb065ee006beb1da48f1ad9b79c..19f07570663727eb2c8c259b91fb073fd0477e8d 100644
--- a/components/metrics/metrics_reporting_scheduler.h
+++ b/components/metrics/metrics_reporting_scheduler.h
@@ -66,6 +66,10 @@ class MetricsReportingScheduler {
   // upload.
   base::TimeDelta upload_interval_;
 
+  // The tick count of the last time log upload has been finished and null if no
+  // upload has been done yet.
+  base::TimeTicks last_upload_finish_time_;
+
   // Indicates that the scheduler is running (i.e., that Start has been called
   // more recently than Stop).
   bool running_;