chrome/browser/segmentation_platform/segmentation_platform_config.cc - chromium/src - Git at Google

 // Copyright 2021 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 "chrome/browser/segmentation_platform/segmentation_platform_config.h"

 #include <memory>

 #include "base/feature_list.h"
 #include "base/metrics/field_trial_params.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/browser/segmentation_platform/default_model/low_user_engagement_model.h"
 #include "components/optimization_guide/proto/models.pb.h"
 #include "components/segmentation_platform/public/config.h"
 #include "components/segmentation_platform/public/features.h"
 #include "components/segmentation_platform/public/model_provider.h"

 #if BUILDFLAG(IS_ANDROID)
 #include "chrome/browser/feature_guide/notifications/feature_notification_guide_service.h"
 #include "chrome/browser/flags/android/cached_feature_flags.h"
 #include "chrome/browser/flags/android/chrome_feature_list.h"
 #include "chrome/browser/segmentation_platform/default_model/chrome_start_model_android.h"
 #include "chrome/browser/segmentation_platform/default_model/query_tiles_model.h"
 #include "chrome/browser/ui/android/start_surface/start_surface_android.h"
 #include "components/query_tiles/switches.h"
 #endif

 using optimization_guide::proto::OptimizationTarget;

 namespace segmentation_platform {

 namespace {

 constexpr char kDefaultModelEnabledParam[] = "enable_default_model";

 // Default TTL for segment selection and unknown selection:

 constexpr int kDummyFeatureSelectionTTLDays = 1;

 constexpr int kChromeLowUserEngagementSelectionTTLDays = 30;

 #if BUILDFLAG(IS_ANDROID)

 constexpr int kAdaptiveToolbarDefaultSelectionTTLDays = 28;

 constexpr int kChromeStartDefaultSelectionTTLDays = 30;
 constexpr int kChromeStartDefaultUnknownTTLDays = 7;
 // See
 // https://source.chromium.org/chromium/chromium/src/+/main:chrome/android/java/src/org/chromium/chrome/browser/query_tiles/QueryTileUtils.java
 const char kNumDaysKeepShowingQueryTiles[] =
     "num_days_keep_showing_query_tiles";
 const char kNumDaysMVCkicksBelowThreshold[] =
     "num_days_mv_clicks_below_threshold";

 // DEFAULT_NUM_DAYS_KEEP_SHOWING_QUERY_TILES
 constexpr int kQueryTilesDefaultSelectionTTLDays = 28;
 // DEFAULT_NUM_DAYS_MV_CLICKS_BELOW_THRESHOLD
 constexpr int kQueryTilesDefaultUnknownTTLDays = 7;
 #endif  // BUILDFLAG(IS_ANDROID)

 #if BUILDFLAG(IS_ANDROID)
 std::unique_ptr<Config> GetConfigForAdaptiveToolbar() {
   auto config = std::make_unique<Config>();
   config->segmentation_key = kAdaptiveToolbarSegmentationKey;

   int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       chrome::android::kAdaptiveButtonInTopToolbarCustomizationV2,
       "segment_selection_ttl_days", kAdaptiveToolbarDefaultSelectionTTLDays);
   config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
   // Do not set unknown TTL so that the platform ignores unknown results.

   // A hardcoded list of segment IDs known to the segmentation platform.
   config->segment_ids = {
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_NEW_TAB,
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_SHARE,
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_VOICE,
   };

   return config;
 }
 #endif

 std::unique_ptr<Config> GetConfigForDummyFeature() {
   auto config = std::make_unique<Config>();
   config->segmentation_key = kDummySegmentationKey;
   config->segment_ids = {
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_DUMMY,
   };
   config->segment_selection_ttl = base::Days(kDummyFeatureSelectionTTLDays);
   config->unknown_selection_ttl = base::Days(kDummyFeatureSelectionTTLDays);
   return config;
 }

 #if BUILDFLAG(IS_ANDROID)
 std::unique_ptr<ModelProvider> GetChromeStartAndroidModel() {
   if (!base::GetFieldTrialParamByFeatureAsBool(
           chrome::android::kStartSurfaceAndroid, kDefaultModelEnabledParam,
           false)) {
     return nullptr;
   }
   return std::make_unique<ChromeStartModel>();
 }

 std::unique_ptr<Config> GetConfigForChromeStartAndroid() {
   auto config = std::make_unique<Config>();
   config->segmentation_key = kChromeStartAndroidSegmentationKey;
   config->segment_ids = {
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_CHROME_START_ANDROID,
   };

   int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       chrome::android::kStartSurfaceAndroid, "segment_selection_ttl_days",
       kChromeStartDefaultSelectionTTLDays);
   int unknown_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       chrome::android::kStartSurfaceAndroid,
       "segment_unknown_selection_ttl_days", kChromeStartDefaultUnknownTTLDays);
   config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
   config->unknown_selection_ttl = base::Days(unknown_selection_ttl_days);

   return config;
 }

 std::unique_ptr<ModelProvider> GetQueryTilesDefaultModel() {
   if (!base::GetFieldTrialParamByFeatureAsBool(
           query_tiles::features::kQueryTilesSegmentation,
           kDefaultModelEnabledParam, false)) {
     return nullptr;
   }
   return std::make_unique<QueryTilesModel>();
 }

 std::unique_ptr<Config> GetConfigForQueryTiles() {
   auto config = std::make_unique<Config>();
   config->segmentation_key = kQueryTilesSegmentationKey;
   config->segment_ids = {
       OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_QUERY_TILES,
   };

   int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       query_tiles::features::kQueryTilesSegmentation,
       kNumDaysKeepShowingQueryTiles, kQueryTilesDefaultSelectionTTLDays);
   int unknown_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       query_tiles::features::kQueryTilesSegmentation,
       kNumDaysMVCkicksBelowThreshold, kQueryTilesDefaultUnknownTTLDays);
   config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
   config->unknown_selection_ttl = base::Days(unknown_selection_ttl_days);
   return config;
 }

 #endif  // BUILDFLAG(IS_ANDROID)

 std::unique_ptr<ModelProvider> GetLowEngagementDefaultModel() {
   if (!base::GetFieldTrialParamByFeatureAsBool(
           features::kSegmentationPlatformLowEngagementFeature,
           kDefaultModelEnabledParam, false)) {
     return nullptr;
   }
   return std::make_unique<LowUserEngagementModel>();
 }

 bool IsLowEngagementFeatureEnabled() {
   // TODO(ssid): Remove this extra feature and change feature guide to use the
   // segmentation defined feature.
 #if BUILDFLAG(IS_ANDROID)
   if (base::FeatureList::IsEnabled(
           feature_guide::features::kSegmentationModelLowEngagedUsers)) {
     return true;
   }
 #endif
   return base::FeatureList::IsEnabled(
       features::kSegmentationPlatformLowEngagementFeature);
 }

 std::unique_ptr<Config> GetConfigForChromeLowUserEngagement() {
   auto config = std::make_unique<Config>();
   config->segmentation_key = kChromeLowUserEngagementSegmentationKey;
   config->segment_ids = {
       OptimizationTarget::
           OPTIMIZATION_TARGET_SEGMENTATION_CHROME_LOW_USER_ENGAGEMENT,
   };

 #if BUILDFLAG(IS_ANDROID)
   int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
       feature_guide::features::kSegmentationModelLowEngagedUsers,
       "segment_selection_ttl_days", kChromeLowUserEngagementSelectionTTLDays);
 #else
   int segment_selection_ttl_days = kChromeLowUserEngagementSelectionTTLDays;
 #endif

   config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
   config->unknown_selection_ttl = base::Days(segment_selection_ttl_days);
   return config;
 }

 }  // namespace

 std::vector<std::unique_ptr<Config>> GetSegmentationPlatformConfig() {
   std::vector<std::unique_ptr<Config>> configs;
   if (base::FeatureList::IsEnabled(
           segmentation_platform::features::kSegmentationPlatformDummyFeature)) {
     configs.emplace_back(GetConfigForDummyFeature());
   }
 #if BUILDFLAG(IS_ANDROID)
   if (base::FeatureList::IsEnabled(
           chrome::android::kAdaptiveButtonInTopToolbarCustomizationV2)) {
     configs.emplace_back(GetConfigForAdaptiveToolbar());
   }
   if (IsStartSurfaceBehaviouralTargetingEnabled()) {
     configs.emplace_back(GetConfigForChromeStartAndroid());
   }
   if (base::FeatureList::IsEnabled(
           query_tiles::features::kQueryTilesSegmentation)) {
     configs.emplace_back(GetConfigForQueryTiles());
   }
 #endif
   if (IsLowEngagementFeatureEnabled()) {
     configs.emplace_back(GetConfigForChromeLowUserEngagement());
   }
   return configs;
 }

 DefaultModelsRegister::DefaultModelsRegister() = default;
 DefaultModelsRegister::~DefaultModelsRegister() = default;

 DefaultModelsRegister& DefaultModelsRegister::GetInstance() {
   static base::NoDestructor<DefaultModelsRegister> instance;
   return *instance;
 }

 std::unique_ptr<ModelProvider> DefaultModelsRegister::GetModelProvider(
     optimization_guide::proto::OptimizationTarget target) {
   auto it = providers_.find(target);
   if (it != providers_.end()) {
     DCHECK(it->second);
     return std::move(it->second);
   }

 #if BUILDFLAG(IS_ANDROID)
   if (target ==
       optimization_guide::proto::OPTIMIZATION_TARGET_SEGMENTATION_QUERY_TILES) {
     return GetQueryTilesDefaultModel();
   }
   if (target == optimization_guide::proto::
                     OPTIMIZATION_TARGET_SEGMENTATION_CHROME_START_ANDROID) {
     return GetChromeStartAndroidModel();
   }
 #endif
   if (target ==
       optimization_guide::proto::
           OPTIMIZATION_TARGET_SEGMENTATION_CHROME_LOW_USER_ENGAGEMENT) {
     return GetLowEngagementDefaultModel();
   }
   return nullptr;
 }

 void DefaultModelsRegister::SetModelForTesting(
     optimization_guide::proto::OptimizationTarget target,
     std::unique_ptr<ModelProvider> provider) {
   providers_[target] = std::move(provider);
 }

 FieldTrialRegisterImpl::FieldTrialRegisterImpl() = default;
 FieldTrialRegisterImpl::~FieldTrialRegisterImpl() = default;

 void FieldTrialRegisterImpl::RegisterFieldTrial(base::StringPiece trial_name,
                                                 base::StringPiece group_name) {
   // The register method is called early in startup once the platform is
   // initialized. So, in most cases the client will register the field trial
   // before uploading the first UMA log of the current session. We do not want
   // to annotate logs from the previous session. (These comes in two types:
   // histograms persisted from the previous session or stability information
   // about the previous session.) Groups are not stable across sessions; we
   // don't know if the current segmentation applies to the previous session.
   // Incidentally, the platform records metrics to track the movement between
   // groups.
   // TODO(ssid): Move to a MetricsProvider approach to fill the groups so we are
   // able to track how often we miss the first session log due to delays in
   // platform initialization.
   ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
       trial_name, group_name,
       variations::SyntheticTrialAnnotationMode::kCurrentLog);
 }

 }  // namespace segmentation_platform
	// Copyright 2021 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 "chrome/browser/segmentation_platform/segmentation_platform_config.h"

	#include <memory>

	#include "base/feature_list.h"
	#include "base/metrics/field_trial_params.h"
	#include "base/time/time.h"
	#include "build/build_config.h"
	#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
	#include "chrome/browser/segmentation_platform/default_model/low_user_engagement_model.h"
	#include "components/optimization_guide/proto/models.pb.h"
	#include "components/segmentation_platform/public/config.h"
	#include "components/segmentation_platform/public/features.h"
	#include "components/segmentation_platform/public/model_provider.h"

	#if BUILDFLAG(IS_ANDROID)
	#include "chrome/browser/feature_guide/notifications/feature_notification_guide_service.h"
	#include "chrome/browser/flags/android/cached_feature_flags.h"
	#include "chrome/browser/flags/android/chrome_feature_list.h"
	#include "chrome/browser/segmentation_platform/default_model/chrome_start_model_android.h"
	#include "chrome/browser/segmentation_platform/default_model/query_tiles_model.h"
	#include "chrome/browser/ui/android/start_surface/start_surface_android.h"
	#include "components/query_tiles/switches.h"
	#endif

	using optimization_guide::proto::OptimizationTarget;

	namespace segmentation_platform {

	namespace {

	constexpr char kDefaultModelEnabledParam[] = "enable_default_model";

	// Default TTL for segment selection and unknown selection:

	constexpr int kDummyFeatureSelectionTTLDays = 1;

	constexpr int kChromeLowUserEngagementSelectionTTLDays = 30;

	#if BUILDFLAG(IS_ANDROID)

	constexpr int kAdaptiveToolbarDefaultSelectionTTLDays = 28;

	constexpr int kChromeStartDefaultSelectionTTLDays = 30;
	constexpr int kChromeStartDefaultUnknownTTLDays = 7;
	// See
	// https://source.chromium.org/chromium/chromium/src/+/main:chrome/android/java/src/org/chromium/chrome/browser/query_tiles/QueryTileUtils.java
	const char kNumDaysKeepShowingQueryTiles[] =
	"num_days_keep_showing_query_tiles";
	const char kNumDaysMVCkicksBelowThreshold[] =
	"num_days_mv_clicks_below_threshold";

	// DEFAULT_NUM_DAYS_KEEP_SHOWING_QUERY_TILES
	constexpr int kQueryTilesDefaultSelectionTTLDays = 28;
	// DEFAULT_NUM_DAYS_MV_CLICKS_BELOW_THRESHOLD
	constexpr int kQueryTilesDefaultUnknownTTLDays = 7;
	#endif // BUILDFLAG(IS_ANDROID)

	#if BUILDFLAG(IS_ANDROID)
	std::unique_ptr<Config> GetConfigForAdaptiveToolbar() {
	auto config = std::make_unique<Config>();
	config->segmentation_key = kAdaptiveToolbarSegmentationKey;

	int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	chrome::android::kAdaptiveButtonInTopToolbarCustomizationV2,
	"segment_selection_ttl_days", kAdaptiveToolbarDefaultSelectionTTLDays);
	config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
	// Do not set unknown TTL so that the platform ignores unknown results.

	// A hardcoded list of segment IDs known to the segmentation platform.
	config->segment_ids = {
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_NEW_TAB,
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_SHARE,
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_VOICE,
	};

	return config;
	}
	#endif

	std::unique_ptr<Config> GetConfigForDummyFeature() {
	auto config = std::make_unique<Config>();
	config->segmentation_key = kDummySegmentationKey;
	config->segment_ids = {
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_DUMMY,
	};
	config->segment_selection_ttl = base::Days(kDummyFeatureSelectionTTLDays);
	config->unknown_selection_ttl = base::Days(kDummyFeatureSelectionTTLDays);
	return config;
	}

	#if BUILDFLAG(IS_ANDROID)
	std::unique_ptr<ModelProvider> GetChromeStartAndroidModel() {
	if (!base::GetFieldTrialParamByFeatureAsBool(
	chrome::android::kStartSurfaceAndroid, kDefaultModelEnabledParam,
	false)) {
	return nullptr;
	}
	return std::make_unique<ChromeStartModel>();
	}

	std::unique_ptr<Config> GetConfigForChromeStartAndroid() {
	auto config = std::make_unique<Config>();
	config->segmentation_key = kChromeStartAndroidSegmentationKey;
	config->segment_ids = {
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_CHROME_START_ANDROID,
	};

	int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	chrome::android::kStartSurfaceAndroid, "segment_selection_ttl_days",
	kChromeStartDefaultSelectionTTLDays);
	int unknown_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	chrome::android::kStartSurfaceAndroid,
	"segment_unknown_selection_ttl_days", kChromeStartDefaultUnknownTTLDays);
	config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
	config->unknown_selection_ttl = base::Days(unknown_selection_ttl_days);

	return config;
	}

	std::unique_ptr<ModelProvider> GetQueryTilesDefaultModel() {
	if (!base::GetFieldTrialParamByFeatureAsBool(
	query_tiles::features::kQueryTilesSegmentation,
	kDefaultModelEnabledParam, false)) {
	return nullptr;
	}
	return std::make_unique<QueryTilesModel>();
	}

	std::unique_ptr<Config> GetConfigForQueryTiles() {
	auto config = std::make_unique<Config>();
	config->segmentation_key = kQueryTilesSegmentationKey;
	config->segment_ids = {
	OptimizationTarget::OPTIMIZATION_TARGET_SEGMENTATION_QUERY_TILES,
	};

	int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	query_tiles::features::kQueryTilesSegmentation,
	kNumDaysKeepShowingQueryTiles, kQueryTilesDefaultSelectionTTLDays);
	int unknown_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	query_tiles::features::kQueryTilesSegmentation,
	kNumDaysMVCkicksBelowThreshold, kQueryTilesDefaultUnknownTTLDays);
	config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
	config->unknown_selection_ttl = base::Days(unknown_selection_ttl_days);
	return config;
	}

	#endif // BUILDFLAG(IS_ANDROID)

	std::unique_ptr<ModelProvider> GetLowEngagementDefaultModel() {
	if (!base::GetFieldTrialParamByFeatureAsBool(
	features::kSegmentationPlatformLowEngagementFeature,
	kDefaultModelEnabledParam, false)) {
	return nullptr;
	}
	return std::make_unique<LowUserEngagementModel>();
	}

	bool IsLowEngagementFeatureEnabled() {
	// TODO(ssid): Remove this extra feature and change feature guide to use the
	// segmentation defined feature.
	#if BUILDFLAG(IS_ANDROID)
	if (base::FeatureList::IsEnabled(
	feature_guide::features::kSegmentationModelLowEngagedUsers)) {
	return true;
	}
	#endif
	return base::FeatureList::IsEnabled(
	features::kSegmentationPlatformLowEngagementFeature);
	}

	std::unique_ptr<Config> GetConfigForChromeLowUserEngagement() {
	auto config = std::make_unique<Config>();
	config->segmentation_key = kChromeLowUserEngagementSegmentationKey;
	config->segment_ids = {
	OptimizationTarget::
	OPTIMIZATION_TARGET_SEGMENTATION_CHROME_LOW_USER_ENGAGEMENT,
	};

	#if BUILDFLAG(IS_ANDROID)
	int segment_selection_ttl_days = base::GetFieldTrialParamByFeatureAsInt(
	feature_guide::features::kSegmentationModelLowEngagedUsers,
	"segment_selection_ttl_days", kChromeLowUserEngagementSelectionTTLDays);
	#else
	int segment_selection_ttl_days = kChromeLowUserEngagementSelectionTTLDays;
	#endif

	config->segment_selection_ttl = base::Days(segment_selection_ttl_days);
	config->unknown_selection_ttl = base::Days(segment_selection_ttl_days);
	return config;
	}

	} // namespace

	std::vector<std::unique_ptr<Config>> GetSegmentationPlatformConfig() {
	std::vector<std::unique_ptr<Config>> configs;
	if (base::FeatureList::IsEnabled(
	segmentation_platform::features::kSegmentationPlatformDummyFeature)) {
	configs.emplace_back(GetConfigForDummyFeature());
	}
	#if BUILDFLAG(IS_ANDROID)
	if (base::FeatureList::IsEnabled(
	chrome::android::kAdaptiveButtonInTopToolbarCustomizationV2)) {
	configs.emplace_back(GetConfigForAdaptiveToolbar());
	}
	if (IsStartSurfaceBehaviouralTargetingEnabled()) {
	configs.emplace_back(GetConfigForChromeStartAndroid());
	}
	if (base::FeatureList::IsEnabled(
	query_tiles::features::kQueryTilesSegmentation)) {
	configs.emplace_back(GetConfigForQueryTiles());
	}
	#endif
	if (IsLowEngagementFeatureEnabled()) {
	configs.emplace_back(GetConfigForChromeLowUserEngagement());
	}
	return configs;
	}

	DefaultModelsRegister::DefaultModelsRegister() = default;
	DefaultModelsRegister::~DefaultModelsRegister() = default;

	DefaultModelsRegister& DefaultModelsRegister::GetInstance() {
	static base::NoDestructor<DefaultModelsRegister> instance;
	return *instance;
	}

	std::unique_ptr<ModelProvider> DefaultModelsRegister::GetModelProvider(
	optimization_guide::proto::OptimizationTarget target) {
	auto it = providers_.find(target);
	if (it != providers_.end()) {
	DCHECK(it->second);
	return std::move(it->second);
	}

	#if BUILDFLAG(IS_ANDROID)
	if (target ==
	optimization_guide::proto::OPTIMIZATION_TARGET_SEGMENTATION_QUERY_TILES) {
	return GetQueryTilesDefaultModel();
	}
	if (target == optimization_guide::proto::
	OPTIMIZATION_TARGET_SEGMENTATION_CHROME_START_ANDROID) {
	return GetChromeStartAndroidModel();
	}
	#endif
	if (target ==
	optimization_guide::proto::
	OPTIMIZATION_TARGET_SEGMENTATION_CHROME_LOW_USER_ENGAGEMENT) {
	return GetLowEngagementDefaultModel();
	}
	return nullptr;
	}

	void DefaultModelsRegister::SetModelForTesting(
	optimization_guide::proto::OptimizationTarget target,
	std::unique_ptr<ModelProvider> provider) {
	providers_[target] = std::move(provider);
	}

	FieldTrialRegisterImpl::FieldTrialRegisterImpl() = default;
	FieldTrialRegisterImpl::~FieldTrialRegisterImpl() = default;

	void FieldTrialRegisterImpl::RegisterFieldTrial(base::StringPiece trial_name,
	base::StringPiece group_name) {
	// The register method is called early in startup once the platform is
	// initialized. So, in most cases the client will register the field trial
	// before uploading the first UMA log of the current session. We do not want
	// to annotate logs from the previous session. (These comes in two types:
	// histograms persisted from the previous session or stability information
	// about the previous session.) Groups are not stable across sessions; we
	// don't know if the current segmentation applies to the previous session.
	// Incidentally, the platform records metrics to track the movement between
	// groups.
	// TODO(ssid): Move to a MetricsProvider approach to fill the groups so we are
	// able to track how often we miss the first session log due to delays in
	// platform initialization.
	ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
	trial_name, group_name,
	variations::SyntheticTrialAnnotationMode::kCurrentLog);
	}

	} // namespace segmentation_platform