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

components/variations/variations_seed_simulator.h

 // 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.
 
 #ifndef COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_
 #define COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 26 matching lines @@
     int kill_best_effort_group_change_count;
 
     // The number of expected group changes that fall in the category of killed
     // experiments that should trigger the "critical" restart mechanism.
     int kill_critical_group_change_count;
 
     Result();
     ~Result();
   };
 
-  // Creates the simulator with the given entropy |provider|.
-  explicit VariationsSeedSimulator(
-      const base::FieldTrial::EntropyProvider& provider);
+  // Creates the simulator with the given default and low entropy providers. The
+  // |low_entropy_provider| will be used for studies that should only use a low
+  // entropy source. This is defined by
+  // VariationsSeedProcessor::ShouldStudyUseLowEntropy, in
+  // variations_seed_processor.h.
+  VariationsSeedSimulator(
+      const base::FieldTrial::EntropyProvider& default_entropy_provider,
+      const base::FieldTrial::EntropyProvider& low_entropy_provider);
   virtual ~VariationsSeedSimulator();
 
   // Computes differences between the current process' field trial state and
   // the result of evaluating |seed| with the given parameters. Returns the
   // results of the simulation as a set of expected group change counts of each
   // type.
   Result SimulateSeedStudies(const VariationsSeed& seed,
                              const std::string& locale,
                              const base::Time& reference_date,
                              const base::Version& version,
@@ skipping 30 matching lines @@
   ChangeType PermanentStudyGroupChanged(const ProcessedStudy& processed_study,
                                         const std::string& selected_group);
 
   // For the given |processed_study| with SESSION consistency, determines if
   // there are enough changes in the study config that restarting will result
   // in a guaranteed different group assignment (or different params) and
   // returns the corresponding ChangeType.
   ChangeType SessionStudyGroupChanged(const ProcessedStudy& filtered_study,
                                       const std::string& selected_group);
 
-  const base::FieldTrial::EntropyProvider& entropy_provider_;
+  const base::FieldTrial::EntropyProvider& default_entropy_provider_;
+  const base::FieldTrial::EntropyProvider& low_entropy_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsSeedSimulator);
 };
 
 }  // namespace variations
 
 #endif  // COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_