Histogram for recording actual log upload interval added.

components/metrics/metrics_reporting_scheduler.cc

Index: components/metrics/metrics_reporting_scheduler.cc
diff --git a/components/metrics/metrics_reporting_scheduler.cc b/components/metrics/metrics_reporting_scheduler.cc
index faf5c623ab4e75a350883e0a84969051fd2a2674..366ce71576c7d4c5b94068f96b7ea41f492e6819 100644
--- a/components/metrics/metrics_reporting_scheduler.cc
+++ b/components/metrics/metrics_reporting_scheduler.cc
@@ -62,6 +62,14 @@ void LogMetricsInitSequence(InitSequence sequence) {
                             INIT_SEQUENCE_ENUM_SIZE);
 }
 
+void LogActualUploadInterval(TimeDelta interval) {
+   UMA_HISTOGRAM_CUSTOM_COUNTS("UMA.ActualLogUploadInterval",
+                               interval.InMinutes(),
+                               1,
+                               base::TimeDelta::FromHours(4).InMinutes(),

[Alexei Svitkine (slow), 2014/10/15 20:44:19]

Let's make this longer to ensure we catch any outliers - how about 12h?

[gayane -on leave until 09-2017, 2014/10/15 21:02:00]

Done.

+                               100);

[Alexei Svitkine (slow), 2014/10/15 20:44:19]

Let's use 50 buckets - I'm not convinced we need 100.

[gayane -on leave until 09-2017, 2014/10/15 21:02:00]

Done.

+}
+
 // Returns upload interval specified for the current experiment running.
 // TODO(gayane): Only for experimenting with upload interval for Android
 // (bug: 17391128). Should be removed once the experiments are done.
@@ -81,6 +89,7 @@ MetricsReportingScheduler::MetricsReportingScheduler(
     const base::Closure& upload_callback)
     : upload_callback_(upload_callback),
       upload_interval_(TimeDelta::FromSeconds(kInitialUploadIntervalSeconds)),
+      last_upload_finish_time_(),

[Alexei Svitkine (slow), 2014/10/15 20:44:19]

This line is not necessary if there's a default ctor for the field.

[gayane -on leave until 09-2017, 2014/10/15 21:02:00]

Done.

       running_(false),
       callback_pending_(false),
       init_task_complete_(false),
@@ -126,6 +135,7 @@ void MetricsReportingScheduler::UploadFinished(bool server_is_healthy,
     upload_interval_ = TimeDelta::FromSeconds(kUnsentLogsIntervalSeconds);
   } else {
     upload_interval_ = GetStandardUploadInterval();
+    last_upload_finish_time_ = base::TimeTicks::Now();
   }
 
   if (running_)
@@ -152,6 +162,12 @@ void MetricsReportingScheduler::TriggerUpload() {
     waiting_for_init_task_complete_ = true;
     return;
   }
+
+  if (!last_upload_finish_time_.is_null()) {
+    LogActualUploadInterval(base::TimeTicks::Now() - last_upload_finish_time_);
+    last_upload_finish_time_.FromInternalValue(0);

[Alexei Svitkine (slow), 2014/10/15 20:44:19]

FromInternalValue is a static method that returns a new object, so this isn't
doing what you think it's doing.

I think you just want:

last_upload_finish_time_ = base::TimeTicks();

[gayane -on leave until 09-2017, 2014/10/15 21:02:00]

Done.

+  }
+
   callback_pending_ = true;
   upload_callback_.Run();
 }