[Variations] Refactor all state used for study filtering into a container struct.

components/variations/study_filtering.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_STUDY_FILTERING_H_
 #define COMPONENTS_VARIATIONS_STUDY_FILTERING_H_
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/time/time.h"
 #include "base/version.h"
 #include "components/variations/processed_study.h"
 #include "components/variations/proto/study.pb.h"
 #include "components/variations/proto/variations_seed.pb.h"
 
 namespace variations {
 
+struct ClientFilterableState;
+
 // Internal functions exposed for testing purposes only.
 namespace internal {
 
 // Checks whether a study is applicable for the given |channel| per |filter|.
-bool CheckStudyChannel(const Study_Filter& filter, Study_Channel channel);
+bool CheckStudyChannel(const Study::Filter& filter, Study::Channel channel);
 
 // Checks whether a study is applicable for the given |form_factor| per
 // |filter|.
-bool CheckStudyFormFactor(const Study_Filter& filter,
-                          Study_FormFactor form_factor);
+bool CheckStudyFormFactor(const Study::Filter& filter,
+                          Study::FormFactor form_factor);
 
 // Checks whether a study is applicable for the given |hardware_class| per
 // |filter|.
-bool CheckStudyHardwareClass(const Study_Filter& filter,
+bool CheckStudyHardwareClass(const Study::Filter& filter,
                              const std::string& hardware_class);
 
 // Checks whether a study is applicable for the given |locale| per |filter|.
-bool CheckStudyLocale(const Study_Filter& filter, const std::string& locale);
+bool CheckStudyLocale(const Study::Filter& filter, const std::string& locale);
 
 // Checks whether a study is applicable for the given |platform| per |filter|.
-bool CheckStudyPlatform(const Study_Filter& filter, Study_Platform platform);
+bool CheckStudyPlatform(const Study::Filter& filter, Study::Platform platform);
 
 // Checks whether a study is applicable for the given date/time per |filter|.
-bool CheckStudyStartDate(const Study_Filter& filter,
+bool CheckStudyStartDate(const Study::Filter& filter,
                          const base::Time& date_time);
 
 // Checks whether a study is applicable for the given date/time per |filter|.
-bool CheckStudyEndDate(const Study_Filter& filter, const base::Time& date_time);
+bool CheckStudyEndDate(const Study::Filter& filter,
+                       const base::Time& date_time);
 
 // Checks whether a study is applicable for the given version per |filter|.
-bool CheckStudyVersion(const Study_Filter& filter,
+bool CheckStudyVersion(const Study::Filter& filter,
                        const base::Version& version);
 
 // Checks whether a study is applicable for the given |country| per |filter|.
-bool CheckStudyCountry(const Study_Filter& filter, const std::string& country);
+bool CheckStudyCountry(const Study::Filter& filter, const std::string& country);
+
+// Returns the country that should be used for filtering this study, depending
+// on whether the study has session or permanent consistency.
+const std::string& GetClientCountryForStudy(
+    const Study& study,
+    const ClientFilterableState& client_state);
 
 // Checks whether |study| is expired using the given date/time.
 bool IsStudyExpired(const Study& study, const base::Time& date_time);
 
-// Returns whether |study| should be disabled according to its restriction
-// parameters.
+// Returns whether |study| should be disabled according to the restriction
+// parameters in the |config|.
 bool ShouldAddStudy(const Study& study,
-                    const std::string& locale,
-                    const base::Time& reference_date,
-                    const base::Version& version,
-                    Study_Channel channel,
-                    Study_FormFactor form_factor,
-                    const std::string& hardware_class,
-                    const std::string& country);
+                    const ClientFilterableState& client_state);
 
 }  // namespace internal
 
-// Filters the list of studies in |seed| and validates and pre-processes them,
-// adding any kept studies to |filtered_studies| list. Ensures that the
-// resulting list will not have more than one study with the same name.
+// Filters the list of studies in |seed| according ot the |client_state|, and
+// validates and pre-processes them, adding any kept studies to the
+// |filtered_studies| list. Ensures that the resulting list will not have more
+// than one study with the same name.
 void FilterAndValidateStudies(const VariationsSeed& seed,
-                              const std::string& locale,
-                              const base::Time& reference_date,
-                              const base::Version& version,
-                              Study_Channel channel,
-                              Study_FormFactor form_factor,
-                              const std::string& hardware_class,
-                              const std::string& session_consistency_country,
-                              const std::string& permanent_consistency_country,
+                              const ClientFilterableState& client_state,
                               std::vector<ProcessedStudy>* filtered_studies);
 
 }  // namespace variations
 
 #endif  // COMPONENTS_VARIATIONS_STUDY_FILTERING_H_