Domain Reliability: Measure backoff/retry time to collectors.

components/domain_reliability/scheduler.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/domain_reliability/scheduler.h"
 
 #include <algorithm>
 
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 122 matching lines @@
 
   VLOG(1) << "Upload to collector " << collector_index_
           << (result.is_success() ? " succeeded." : " failed.");
 
   net::BackoffEntry* backoff = collectors_[collector_index_];
   collector_index_ = kInvalidCollectorIndex;
 
   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,
     // since upload failed.
     upload_pending_ = true;
     first_beacon_time_ = old_first_beacon_time_;
   }
 
   last_upload_end_time_ = time_->NowTicks();
   last_upload_success_ = result.is_success();
@@ skipping 104 matching lines @@
       min_index = i;
     }
   }
 
   DCHECK_NE(kInvalidCollectorIndex, min_index);
   *upload_time_out = min_time;
   *collector_index_out = min_index;
 }
 
 }  // namespace domain_reliability