Use low entropy for studies that send experiment IDs to Google properties.

components/variations/variations_seed_simulator.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/variations/variations_seed_simulator.h"
 
 #include <stddef.h>
 
 #include <map>
 
 #include "base/metrics/field_trial.h"
 #include "components/variations/processed_study.h"
 #include "components/variations/proto/study.pb.h"
 #include "components/variations/study_filtering.h"
 #include "components/variations/variations_associated_data.h"
+#include "components/variations/variations_seed_processor.h"
 
 namespace variations {
 
 namespace {
 
 // Fills in |current_state| with the current process' active field trials, as a
 // map of trial names to group names.
 void GetCurrentTrialState(std::map<std::string, std::string>* current_state) {
   base::FieldTrial::ActiveGroups trial_groups;
   base::FieldTrialList::GetActiveFieldTrialGroups(&trial_groups);
@@ skipping 70 matching lines @@
 VariationsSeedSimulator::Result::Result()
     : normal_group_change_count(0),
       kill_best_effort_group_change_count(0),
       kill_critical_group_change_count(0) {
 }
 
 VariationsSeedSimulator::Result::~Result() {
 }
 
 VariationsSeedSimulator::VariationsSeedSimulator(
-    const base::FieldTrial::EntropyProvider& entropy_provider)
-    : entropy_provider_(entropy_provider) {
-}
+    const base::FieldTrial::EntropyProvider& default_entropy_provider,
+    const base::FieldTrial::EntropyProvider& low_entropy_provider)
+    : default_entropy_provider_(default_entropy_provider),
+      low_entropy_provider_(low_entropy_provider) {}
 
 VariationsSeedSimulator::~VariationsSeedSimulator() {
 }
 
 VariationsSeedSimulator::Result VariationsSeedSimulator::SimulateSeedStudies(
     const VariationsSeed& seed,
     const std::string& locale,
     const base::Time& reference_date,
     const base::Version& version,
     Study_Channel channel,
@@ skipping 83 matching lines @@
   return CHANGED;
 }
 
 VariationsSeedSimulator::ChangeType
 VariationsSeedSimulator::PermanentStudyGroupChanged(
     const ProcessedStudy& processed_study,
     const std::string& selected_group) {
   const Study& study = *processed_study.study();
   DCHECK_EQ(Study_Consistency_PERMANENT, study.consistency());
 
-  const std::string simulated_group = SimulateGroupAssignment(entropy_provider_,
-                                                              processed_study);
+  const base::FieldTrial::EntropyProvider& entropy_provider =
+      VariationsSeedProcessor::ShouldStudyUseLowEntropy(study)
+          ? low_entropy_provider_
+          : default_entropy_provider_;
+
+  const std::string simulated_group =
+      SimulateGroupAssignment(entropy_provider, processed_study);
   const Study_Experiment* experiment = FindExperiment(study, selected_group);
   if (simulated_group != selected_group) {
     if (experiment)
       return ConvertExperimentTypeToChangeType(experiment->type());
     return CHANGED;
   }
 
   // Current group exists in the study - check whether its params changed.
   DCHECK(experiment);
   if (!VariationParamsAreEqual(study, *experiment))
@@ skipping 25 matching lines @@
     return ConvertExperimentTypeToChangeType(experiment->type());
   }
 
   // Current group exists in the study - check whether its params changed.
   if (!VariationParamsAreEqual(study, *experiment))
     return ConvertExperimentTypeToChangeType(experiment->type());
   return NO_CHANGE;
 }
 
 }  // namespace variations