chrome/browser/chrome_browser_field_trials.cc

   1 // Copyright 2012 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/chrome_browser_field_trials.h"
   6
   7 #include <string>
   8
   9 #include "base/command_line.h"
  10 #include "base/feature_list.h"
  11 #include "base/files/file_util.h"
  12 #include "base/metrics/field_trial.h"
  13 #include "base/path_service.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/time/time.h"
  16 #include "build/build_config.h"
  17 #include "build/chromeos_buildflags.h"
  18 #include "chrome/browser/metrics/chrome_browser_sampling_trials.h"
  19 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
  20 #include "chrome/browser/metrics/chrome_metrics_service_client.h"
  21 #include "chrome/browser/ui/startup/first_run_service.h"
  22 #include "chrome/common/chrome_paths.h"
  23 #include "chrome/common/chrome_switches.h"
  24 #include "components/metrics/metrics_pref_names.h"
  25 #include "components/metrics/persistent_histograms.h"
  26 #include "components/signin/public/base/signin_buildflags.h"
  27 #include "components/version_info/version_info.h"
  28
  29 #if BUILDFLAG(IS_ANDROID)
  30 #include "base/android/build_info.h"
  31 #include "base/android/bundle_utils.h"
  32 #include "base/task/thread_pool/environment_config.h"
  33 #include "chrome/browser/android/flags/chrome_cached_flags.h"
  34 #include "chrome/browser/android/signin/fre_mobile_identity_consistency_field_trial.h"
  35 #include "chrome/browser/flags/android/chrome_feature_list.h"
  36 #include "chrome/common/chrome_features.h"
  37 #endif
  38
  39 #if BUILDFLAG(IS_CHROMEOS_ASH)
  40 #include "chrome/common/channel_info.h"
  41 #include "chromeos/ash/components/login/auth/recovery/recovery_utils.h"
  42 #include "chromeos/ash/services/multidevice_setup/public/cpp/first_run_field_trial.h"
  43 #endif
  44
  45 #if BUILDFLAG(IS_CHROMEOS_LACROS)
  46 // GN doesn't understand conditional includes, so we need nogncheck here.
  47 // See crbug.com/1125897.
  48 #include "chromeos/startup/startup.h"  // nogncheck
  49 #endif
  50
  51 ChromeBrowserFieldTrials::ChromeBrowserFieldTrials(PrefService* local_state)
  52     : local_state_(local_state) {
  53   DCHECK(local_state_);
  54 }
  55
  56 ChromeBrowserFieldTrials::~ChromeBrowserFieldTrials() = default;
  57
  58 void ChromeBrowserFieldTrials::OnVariationsSetupComplete() {
  59 #if BUILDFLAG(IS_FUCHSIA) || BUILDFLAG(IS_CHROMEOS_LACROS)
  60   // Persistent histograms must be enabled ASAP, but depends on Features.
  61   // For non-Fuchsia platforms, it is enabled earlier on, and is not controlled
  62   // by variations.
  63   // See //chrome/app/chrome_main_delegate.cc.
  64   bool histogram_init_and_cleanup = true;
  65 #if BUILDFLAG(IS_CHROMEOS_LACROS)
  66   // For Lacros, when prelaunching at login screen, we want to postpone the
  67   // initialization and cleanup of persistent histograms to when the user has
  68   // logged in and the cryptohome is accessible.
  69   histogram_init_and_cleanup &= chromeos::IsLaunchedWithPostLoginParams();
  70 #endif
  71   base::FilePath metrics_dir;
  72   if (histogram_init_and_cleanup) {
  73     if (base::PathService::Get(chrome::DIR_USER_DATA, &metrics_dir)) {
  74       InstantiatePersistentHistogramsWithFeaturesAndCleanup(metrics_dir);
  75     } else {
  76       NOTREACHED();
  77     }
  78   }
  79 #endif  // BUILDFLAG(IS_FUCHSIA) || BUILDFLAG(IS_CHROMEOS_LACROS)
  80 }
  81
  82 void ChromeBrowserFieldTrials::SetUpClientSideFieldTrials(
  83     bool has_seed,
  84     const variations::EntropyProviders& entropy_providers,
  85     base::FeatureList* feature_list) {
  86   // Only create the fallback trials if there isn't already a variations seed
  87   // being applied. This should occur during first run when first-run variations
  88   // isn't supported. It's assumed that, if there is a seed, then it either
  89   // contains the relevant studies, or is intentionally omitted, so no fallback
  90   // is needed. The exception is for sampling trials. Fallback trials are
  91   // created even if no variations seed was applied. This allows testing the
  92   // fallback code by intentionally omitting the sampling trial from a
  93   // variations seed.
  94   metrics::CreateFallbackSamplingTrialsIfNeeded(
  95       entropy_providers.default_entropy(), feature_list);
  96   metrics::CreateFallbackUkmSamplingTrialIfNeeded(
  97       entropy_providers.default_entropy(), feature_list);
  98 #if BUILDFLAG(IS_CHROMEOS_ASH)
  99   // For this feature we will use the client-side trial for rollout. The
 100   // server-side/Finch config will be used only as a kill-switch. If it's
 101   // configured - it will override the local trial.
 102   ash::CreateFallbackFieldTrialForRecovery(
 103       chrome::GetChannel() == version_info::Channel::STABLE, feature_list);
 104 #endif
 105   if (!has_seed) {
 106 #if BUILDFLAG(IS_CHROMEOS_ASH)
 107     ash::multidevice_setup::CreateFirstRunFieldTrial(feature_list);
 108 #endif
 109   }
 110 #if BUILDFLAG(ENABLE_DICE_SUPPORT) && !BUILDFLAG(IS_WIN)
 111   FirstRunService::SetUpClientSideFieldTrialIfNeeded(
 112       entropy_providers.default_entropy(), feature_list);
 113 #endif
 114
 115 #if BUILDFLAG(IS_ANDROID)
 116   // RegisterSyntheticTrials doesn't have access to entropy providers which are
 117   // needed to verify group consistency for
 118   // FREMobileIdentityConsistencySynthetic and decide whether to assign
 119   // a variation ID to that study. To work around that - grab the variation ID
 120   // here and perform the actual registration in RegisterSyntheticTrials().
 121   fre_consistency_trial_variation_id_ =
 122       fre_mobile_identity_consistency_field_trial::GetFREFieldTrialVariationId(
 123           entropy_providers.low_entropy_value(),
 124           entropy_providers.low_entropy_domain());
 125 #endif  // BUILDFLAG(IS_ANDROID)
 126 }
 127
 128 void ChromeBrowserFieldTrials::RegisterSyntheticTrials() {
 129 #if BUILDFLAG(IS_ANDROID)
 130   static constexpr char kReachedCodeProfilerTrial[] =
 131       "ReachedCodeProfilerSynthetic2";
 132   std::string reached_code_profiler_group =
 133       chrome::android::GetReachedCodeProfilerTrialGroup();
 134   if (!reached_code_profiler_group.empty()) {
 135     ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
 136         kReachedCodeProfilerTrial, reached_code_profiler_group);
 137   }
 138
 139   {
 140     // BackgroundThreadPoolSynthetic field trial.
 141     const char* group_name;
 142     // Target group as indicated by finch feature.
 143     bool feature_enabled =
 144         base::FeatureList::IsEnabled(chrome::android::kBackgroundThreadPool);
 145     // Whether the feature was overridden by either the commandline or Finch.
 146     bool feature_overridden =
 147         base::FeatureList::GetInstance()->IsFeatureOverridden(
 148             chrome::android::kBackgroundThreadPool.name);
 149     // Whether the feature was overridden manually via the commandline.
 150     bool cmdline_overridden =
 151         feature_overridden &&
 152         base::FeatureList::GetInstance()->IsFeatureOverriddenFromCommandLine(
 153             chrome::android::kBackgroundThreadPool.name);
 154     // The finch feature value is cached by Java in a setting and applied via a
 155     // command line flag. Check if this has happened -- it may not have happened
 156     // if this is the first startup after the feature is enabled.
 157     bool actually_enabled =
 158         base::internal::CanUseBackgroundThreadTypeForWorkerThread();
 159     // Use the default group if either the feature wasn't overridden or if the
 160     // feature target state and actual state don't agree. Also separate users
 161     // that override the feature via the commandline into separate groups.
 162     if (actually_enabled != feature_enabled || !feature_overridden) {
 163       group_name = "Default";
 164     } else if (cmdline_overridden && feature_enabled) {
 165       group_name = "ForceEnabled";
 166     } else if (cmdline_overridden && !feature_enabled) {
 167       group_name = "ForceDisabled";
 168     } else if (feature_enabled) {
 169       group_name = "Enabled";
 170     } else {
 171       group_name = "Disabled";
 172     }
 173     static constexpr char kBackgroundThreadPoolTrial[] =
 174         "BackgroundThreadPoolSynthetic";
 175     ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
 176         kBackgroundThreadPoolTrial, group_name);
 177   }
 178
 179   // MobileIdentityConsistencyFREVariationsSynthetic field trial.
 180   // This trial experiments with different title and subtitle variation in
 181   // the FRE UI. This is a follow up experiment to
 182   // MobileIdentityConsistencyFRESynthetic.
 183   static constexpr char kFREMobileIdentityConsistencyVariationsTrial[] =
 184       "FREMobileIdentityConsistencyVariationsSynthetic";
 185   const std::string variation_group =
 186       fre_mobile_identity_consistency_field_trial::GetFREFieldTrialGroupName();
 187   ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
 188       kFREMobileIdentityConsistencyVariationsTrial, variation_group,
 189       variations::SyntheticTrialAnnotationMode::kCurrentLog);
 190   if (fre_consistency_trial_variation_id_ != variations::EMPTY_ID) {
 191     variations::AssociateGoogleVariationID(
 192         variations::GOOGLE_WEB_PROPERTIES_ANY_CONTEXT,
 193         kFREMobileIdentityConsistencyVariationsTrial, variation_group,
 194         fre_consistency_trial_variation_id_);
 195   }
 196 #endif  // BUILDFLAG(IS_ANDROID)
 197 #if BUILDFLAG(ENABLE_DICE_SUPPORT)
 198   FirstRunService::EnsureStickToFirstRunCohort();
 199 #endif
 200 }