Revert of Domain Reliability: Switch to BackoffEntry in Scheduler

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 fb5f8577f5b7bc7a726a964266e636facdda0530..636130c9eb0f9a4fdcf16caa1c4bff3d4a04e997 100644
--- a/components/domain_reliability/scheduler.cc
+++ b/components/domain_reliability/scheduler.cc
@@ -23,11 +23,6 @@
 const char* kMinimumUploadDelayFieldTrialName = "DomRel-MinimumUploadDelay";
 const char* kMaximumUploadDelayFieldTrialName = "DomRel-MaximumUploadDelay";
 const char* kUploadRetryIntervalFieldTrialName = "DomRel-UploadRetryInterval";
-
-// Fixed elements of backoff policy
-const double kMultiplyFactor = 2.0;
-const double kJitterFactor = 0.1;
-const int64 kMaximumBackoffMs = 60 * 1000 * 1000;
 
 unsigned GetUnsignedFieldTrialValueOrDefault(std::string field_trial_name,
                                              unsigned default_value) {
@@ -74,6 +69,7 @@
     const Params& params,
     const ScheduleUploadCallback& callback)
     : time_(time),
+      collectors_(num_collectors),
       params_(params),
       callback_(callback),
       upload_pending_(false),
@@ -81,19 +77,6 @@
       upload_running_(false),
       collector_index_(kInvalidCollectorIndex),
       last_upload_finished_(false) {
-  backoff_policy_.num_errors_to_ignore = 0;
-  backoff_policy_.initial_delay_ms =
-      params.upload_retry_interval.InMilliseconds();
-  backoff_policy_.multiply_factor = kMultiplyFactor;
-  backoff_policy_.jitter_factor = kJitterFactor;
-  backoff_policy_.maximum_backoff_ms = kMaximumBackoffMs;
-  backoff_policy_.entry_lifetime_ms = 0;
-  backoff_policy_.always_use_initial_delay = false;
-
-  for (size_t i = 0; i < num_collectors; ++i) {
-    collectors_.push_back(
-      new MockableTimeBackoffEntry(&backoff_policy_, time_));
-  }
 }
 
 DomainReliabilityScheduler::~DomainReliabilityScheduler() {}
@@ -133,20 +116,30 @@
   VLOG(1) << "Upload to collector " << collector_index_
           << (success ? " succeeded." : " failed.");
 
-  net::BackoffEntry* backoff = collectors_[collector_index_];
+  CollectorState* collector = &collectors_[collector_index_];
   collector_index_ = kInvalidCollectorIndex;
-  backoff->InformOfRequest(success);
-
-  if (!success) {
+
+  if (success) {
+    collector->failures = 0;
+  } else {
     // 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();
+
+    ++collector->failures;
+  }
+
+  base::TimeTicks now = time_->NowTicks();
+  base::TimeDelta retry_interval = GetUploadRetryInterval(collector->failures);
+  collector->next_upload = now + retry_interval;
+
+  last_upload_end_time_ = now;
   last_upload_success_ = success;
   last_upload_finished_ = true;
+
+  VLOG(1) << "Next upload to collector at least "
+          << retry_interval.InSeconds() << " seconds from now.";
 
   MaybeScheduleUpload();
 }
@@ -177,11 +170,10 @@
 
   base::ListValue* collectors = new base::ListValue();
   for (size_t i = 0; i < collectors_.size(); ++i) {
-    const net::BackoffEntry* backoff = collectors_[i];
+    const CollectorState* state = &collectors_[i];
     base::DictionaryValue* value = new base::DictionaryValue();
-    value->SetInteger("failures", backoff->failure_count());
-    value->SetInteger("next_upload",
-        (backoff->GetReleaseTime() - now).InSeconds());
+    value->SetInteger("failures", state->failures);
+    value->SetInteger("next_upload", (state->next_upload - now).InSeconds());
     collectors->Append(value);
   }
   data->Set("collectors", collectors);
@@ -189,9 +181,7 @@
   return data;
 }
 
-void DomainReliabilityScheduler::MakeDeterministicForTesting() {
-  backoff_policy_.jitter_factor = 0.0;
-}
+DomainReliabilityScheduler::CollectorState::CollectorState() : failures(0) {}
 
 void DomainReliabilityScheduler::MaybeScheduleUpload() {
   if (!upload_pending_ || upload_scheduled_ || upload_running_)
@@ -238,18 +228,16 @@
   size_t min_index = kInvalidCollectorIndex;
 
   for (size_t i = 0; i < collectors_.size(); ++i) {
-    net::BackoffEntry* backoff = collectors_[i];
+    CollectorState* collector = &collectors_[i];
     // If a collector is usable, use the first one in the list.
-    if (!backoff->ShouldRejectRequest()) {
+    if (collector->failures == 0 || collector->next_upload <= now) {
       min_time = now;
       min_index = i;
       break;
-    }
-
     // If not, keep track of which will be usable soonest:
-    base::TimeTicks time = backoff->GetReleaseTime();
-    if (min_index == kInvalidCollectorIndex || time < min_time) {
-      min_time = time;
+    } else if (min_index == kInvalidCollectorIndex ||
+        collector->next_upload < min_time) {
+      min_time = collector->next_upload;
       min_index = i;
     }
   }
@@ -259,4 +247,16 @@
   *collector_index_out = min_index;
 }
 
+base::TimeDelta DomainReliabilityScheduler::GetUploadRetryInterval(
+    unsigned failures) {
+  if (failures == 0)
+    return base::TimeDelta::FromSeconds(0);
+  else {
+    // Don't back off more than 64x the original delay.
+    if (failures > 7)
+      failures = 7;
+    return params_.upload_retry_interval * (1 << (failures - 1));
+  }
+}
+
 }  // namespace domain_reliability