Move API for field trial params to base from variations.

base/metrics/field_trial_params.cc

Index: base/metrics/field_trial_params.cc
diff --git a/components/variations/variations_associated_data.cc b/base/metrics/field_trial_params.cc
similarity index 27%
copy from components/variations/variations_associated_data.cc
copy to base/metrics/field_trial_params.cc
index ec696a3e37fd0bd5d7db10c0f98d6c49754a5235..bcefa8944fb7bd79aca79d90b916bcd0e796e3f2 100644
--- a/components/variations/variations_associated_data.cc
+++ b/base/metrics/field_trial_params.cc
@@ -1,156 +1,17 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2017 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_associated_data.h"
-
-#include <map>
-#include <utility>
-#include <vector>
+#include "base/metrics/field_trial_params.h"
 
 #include "base/feature_list.h"
-#include "base/macros.h"
-#include "base/memory/singleton.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/field_trial_param_associator.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/strings/string_split.h"
-#include "components/variations/variations_http_header_provider.h"
-
-namespace variations {
-
-namespace {
-
-// The internal singleton accessor for the map, used to keep it thread-safe.
-class GroupMapAccessor {
- public:
-  typedef std::map<ActiveGroupId, VariationID, ActiveGroupIdCompare>
-      GroupToIDMap;
-
-  // Retrieve the singleton.
-  static GroupMapAccessor* GetInstance() {
-    return base::Singleton<GroupMapAccessor>::get();
-  }
-
-  // Note that this normally only sets the ID for a group the first time, unless
-  // |force| is set to true, in which case it will always override it.
-  void AssociateID(IDCollectionKey key,
-                   const ActiveGroupId& group_identifier,
-                   const VariationID id,
-                   const bool force) {
-#if !defined(NDEBUG)
-    DCHECK_EQ(4, ID_COLLECTION_COUNT);
-    // Ensure that at most one of the trigger/non-trigger/signed-in web property
-    // IDs are set.
-    if (key == GOOGLE_WEB_PROPERTIES || key == GOOGLE_WEB_PROPERTIES_TRIGGER ||
-        key == GOOGLE_WEB_PROPERTIES_SIGNED_IN) {
-      if (key != GOOGLE_WEB_PROPERTIES)
-        DCHECK_EQ(EMPTY_ID, GetID(GOOGLE_WEB_PROPERTIES, group_identifier));
-      if (key != GOOGLE_WEB_PROPERTIES_TRIGGER) {
-        DCHECK_EQ(EMPTY_ID,
-                  GetID(GOOGLE_WEB_PROPERTIES_TRIGGER, group_identifier));
-      }
-      if (key != GOOGLE_WEB_PROPERTIES_SIGNED_IN) {
-        DCHECK_EQ(EMPTY_ID,
-                  GetID(GOOGLE_WEB_PROPERTIES_SIGNED_IN, group_identifier));
-      }
-    }
-
-    // Validate that all collections with this |group_identifier| have the same
-    // associated ID.
-    for (int i = 0; i < ID_COLLECTION_COUNT; ++i) {
-      IDCollectionKey other_key = static_cast<IDCollectionKey>(i);
-      if (other_key == key)
-        continue;
-      VariationID other_id = GetID(other_key, group_identifier);
-      DCHECK(other_id == EMPTY_ID || other_id == id);
-    }
-#endif
-
-    base::AutoLock scoped_lock(lock_);
 
-    GroupToIDMap* group_to_id_map = GetGroupToIDMap(key);
-    if (force ||
-        group_to_id_map->find(group_identifier) == group_to_id_map->end())
-      (*group_to_id_map)[group_identifier] = id;
-  }
-
-  VariationID GetID(IDCollectionKey key,
-                    const ActiveGroupId& group_identifier) {
-    base::AutoLock scoped_lock(lock_);
-    GroupToIDMap* group_to_id_map = GetGroupToIDMap(key);
-    GroupToIDMap::const_iterator it = group_to_id_map->find(group_identifier);
-    if (it == group_to_id_map->end())
-      return EMPTY_ID;
-    return it->second;
-  }
-
-  void ClearAllMapsForTesting() {
-    base::AutoLock scoped_lock(lock_);
-
-    for (int i = 0; i < ID_COLLECTION_COUNT; ++i) {
-      GroupToIDMap* map = GetGroupToIDMap(static_cast<IDCollectionKey>(i));
-      DCHECK(map);
-      map->clear();
-    }
-  }
-
- private:
-  friend struct base::DefaultSingletonTraits<GroupMapAccessor>;
-
-  // Retrieves the GroupToIDMap for |key|.
-  GroupToIDMap* GetGroupToIDMap(IDCollectionKey key) {
-    return &group_to_id_maps_[key];
-  }
+namespace base {
 
-  GroupMapAccessor() {
-    group_to_id_maps_.resize(ID_COLLECTION_COUNT);
-  }
-  ~GroupMapAccessor() {}
-
-  base::Lock lock_;
-  std::vector<GroupToIDMap> group_to_id_maps_;
-
-  DISALLOW_COPY_AND_ASSIGN(GroupMapAccessor);
-};
-}  // namespace
-
-void AssociateGoogleVariationID(IDCollectionKey key,
-                                const std::string& trial_name,
-                                const std::string& group_name,
-                                VariationID id) {
-  GroupMapAccessor::GetInstance()->AssociateID(
-      key, MakeActiveGroupId(trial_name, group_name), id, false);
-}
-
-void AssociateGoogleVariationIDForce(IDCollectionKey key,
-                                     const std::string& trial_name,
-                                     const std::string& group_name,
-                                     VariationID id) {
-  AssociateGoogleVariationIDForceHashes(
-      key, MakeActiveGroupId(trial_name, group_name), id);
-}
-
-void AssociateGoogleVariationIDForceHashes(IDCollectionKey key,
-                                           const ActiveGroupId& active_group,
-                                           VariationID id) {
-  GroupMapAccessor::GetInstance()->AssociateID(key, active_group, id, true);
-}
-
-VariationID GetGoogleVariationID(IDCollectionKey key,
-                                 const std::string& trial_name,
-                                 const std::string& group_name) {
-  return GetGoogleVariationIDFromHashes(
-      key, MakeActiveGroupId(trial_name, group_name));
-}
-
-VariationID GetGoogleVariationIDFromHashes(
-    IDCollectionKey key,
-    const ActiveGroupId& active_group) {
-  return GroupMapAccessor::GetInstance()->GetID(key, active_group);
-}
-
-bool AssociateVariationParams(
+bool AssociateFieldTrialParams(
     const std::string& trial_name,
     const std::string& group_name,
     const std::map<std::string, std::string>& params) {
@@ -158,14 +19,14 @@ bool AssociateVariationParams(
       ->AssociateFieldTrialParams(trial_name, group_name, params);
 }
 
-bool GetVariationParams(const std::string& trial_name,
-                        std::map<std::string, std::string>* params) {
+bool GetFieldTrialParams(const std::string& trial_name,
+                         std::map<std::string, std::string>* params) {
   return base::FieldTrialParamAssociator::GetInstance()->GetFieldTrialParams(
       trial_name, params);
 }
 
-bool GetVariationParamsByFeature(const base::Feature& feature,
-                                 std::map<std::string, std::string>* params) {
+bool GetFieldTrialParamsByFeature(const base::Feature& feature,
+                                  std::map<std::string, std::string>* params) {
   if (!base::FeatureList::IsEnabled(feature))
     return false;
 
@@ -173,13 +34,13 @@ bool GetVariationParamsByFeature(const base::Feature& feature,
   if (!trial)
     return false;
 
-  return GetVariationParams(trial->trial_name(), params);
+  return GetFieldTrialParams(trial->trial_name(), params);
 }
 
-std::string GetVariationParamValue(const std::string& trial_name,
-                                   const std::string& param_name) {
+std::string GetFieldTrialParamValue(const std::string& trial_name,
+                                    const std::string& param_name) {
   std::map<std::string, std::string> params;
-  if (GetVariationParams(trial_name, &params)) {
+  if (GetFieldTrialParams(trial_name, &params)) {
     std::map<std::string, std::string>::iterator it = params.find(param_name);
     if (it != params.end())
       return it->second;
@@ -187,8 +48,8 @@ std::string GetVariationParamValue(const std::string& trial_name,
   return std::string();
 }
 
-std::string GetVariationParamValueByFeature(const base::Feature& feature,
-                                            const std::string& param_name) {
+std::string GetFieldTrialParamValueByFeature(const base::Feature& feature,
+                                             const std::string& param_name) {
   if (!base::FeatureList::IsEnabled(feature))
     return std::string();
 
@@ -196,18 +57,18 @@ std::string GetVariationParamValueByFeature(const base::Feature& feature,
   if (!trial)
     return std::string();
 
-  return GetVariationParamValue(trial->trial_name(), param_name);
+  return GetFieldTrialParamValue(trial->trial_name(), param_name);
 }
 
-int GetVariationParamByFeatureAsInt(const base::Feature& feature,
-                                    const std::string& param_name,
-                                    int default_value) {
+int GetFieldTrialParamByFeatureAsInt(const base::Feature& feature,
+                                     const std::string& param_name,
+                                     int default_value) {
   std::string value_as_string =
-      GetVariationParamValueByFeature(feature, param_name);
+      GetFieldTrialParamValueByFeature(feature, param_name);
   int value_as_int = 0;
   if (!base::StringToInt(value_as_string, &value_as_int)) {
     if (!value_as_string.empty()) {
-      DLOG(WARNING) << "Failed to parse variation param " << param_name
+      DLOG(WARNING) << "Failed to parse field trial param " << param_name
                     << " with string value " << value_as_string
                     << " under feature " << feature.name
                     << " into an int. Falling back to default value of "
@@ -218,15 +79,15 @@ int GetVariationParamByFeatureAsInt(const base::Feature& feature,
   return value_as_int;
 }
 
-double GetVariationParamByFeatureAsDouble(const base::Feature& feature,
-                                          const std::string& param_name,
-                                          double default_value) {
+double GetFieldTrialParamByFeatureAsDouble(const base::Feature& feature,
+                                           const std::string& param_name,
+                                           double default_value) {
   std::string value_as_string =
-      GetVariationParamValueByFeature(feature, param_name);
+      GetFieldTrialParamValueByFeature(feature, param_name);
   double value_as_double = 0;
   if (!base::StringToDouble(value_as_string, &value_as_double)) {
     if (!value_as_string.empty()) {
-      DLOG(WARNING) << "Failed to parse variation param " << param_name
+      DLOG(WARNING) << "Failed to parse field trial param " << param_name
                     << " with string value " << value_as_string
                     << " under feature " << feature.name
                     << " into a double. Falling back to default value of "
@@ -237,18 +98,18 @@ double GetVariationParamByFeatureAsDouble(const base::Feature& feature,
   return value_as_double;
 }
 
-bool GetVariationParamByFeatureAsBool(const base::Feature& feature,
-                                      const std::string& param_name,
-                                      bool default_value) {
+bool GetFieldTrialParamByFeatureAsBool(const base::Feature& feature,
+                                       const std::string& param_name,
+                                       bool default_value) {
   std::string value_as_string =
-      variations::GetVariationParamValueByFeature(feature, param_name);
+      GetFieldTrialParamValueByFeature(feature, param_name);
   if (value_as_string == "true")
     return true;
   if (value_as_string == "false")
     return false;
 
   if (!value_as_string.empty()) {
-    DLOG(WARNING) << "Failed to parse variation param " << param_name
+    DLOG(WARNING) << "Failed to parse field trial param " << param_name
                   << " with string value " << value_as_string
                   << " under feature " << feature.name
                   << " into a bool. Falling back to default value of "
@@ -257,18 +118,4 @@ bool GetVariationParamByFeatureAsBool(const base::Feature& feature,
   return default_value;
 }
 
-// Functions below are exposed for testing explicitly behind this namespace.
-// They simply wrap existing functions in this file.
-namespace testing {
-
-void ClearAllVariationIDs() {
-  GroupMapAccessor::GetInstance()->ClearAllMapsForTesting();
-}
-
-void ClearAllVariationParams() {
-  base::FieldTrialParamAssociator::GetInstance()->ClearAllParamsForTesting();
-}
-
-}  // namespace testing
-
-}  // namespace variations
+}  // namespace base