Domain Reliability: Measure backoff/retry time to collectors.

components/domain_reliability/scheduler.cc

Index: components/domain_reliability/scheduler.cc
diff --git a/components/domain_reliability/scheduler.cc b/components/domain_reliability/scheduler.cc
index 5bcff24486419a81dda989a673288a15ea6a98a5..2fc80bbb5a4908b55f453d5d7adb0022751383bc 100644
--- a/components/domain_reliability/scheduler.cc
+++ b/components/domain_reliability/scheduler.cc
@@ -140,6 +140,7 @@ void DomainReliabilityScheduler::OnUploadComplete(
   backoff->InformOfRequest(result.is_success());
   if (result.is_retry_after())
     backoff->SetCustomReleaseTime(time_->NowTicks() + result.retry_after);
+  last_collector_retry_delay_ = backoff->GetTimeUntilRelease();

[davidben, 2015/02/10 19:00:00]

This will also record in the success case, right? What does BackoffEntry do
there? Will it give you a spike of zeros?

[davidben, 2015/02/10 19:10:36]

Ah, I see you even mentioned it in histograms.xml. Missed that on my first pass
somehow.

 
   if (!result.is_success()) {
     // Restore upload_pending_ and first_beacon_time_ to pre-upload state,