Add Field Trial Testing Support to iOS

ios/chrome/browser/ios_chrome_main_parts.mm

 // Copyright 2016 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 "ios/chrome/browser/ios_chrome_main_parts.h"
 
 #include "base/base_switches.h"
 #include "base/feature_list.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 10 matching lines @@
 #include "components/metrics/metrics_service.h"
 #include "components/metrics/profiler/ios/ios_tracking_synchronizer_delegate.h"
 #include "components/metrics/profiler/tracking_synchronizer.h"
 #include "components/metrics_services_manager/metrics_services_manager.h"
 #include "components/open_from_clipboard/clipboard_recent_content.h"
 #include "components/prefs/json_pref_store.h"
 #include "components/prefs/pref_service.h"
 #include "components/rappor/rappor_service.h"
 #include "components/task_scheduler_util/initialization_util.h"
 #include "components/translate/core/browser/translate_download_manager.h"
+#include "components/variations/field_trial_config/field_trial_util.h"
 #include "components/variations/service/variations_service.h"
 #include "components/variations/variations_http_header_provider.h"
+#include "components/variations/variations_switches.h"
 #include "ios/chrome/browser/about_flags.h"
 #include "ios/chrome/browser/application_context_impl.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state_manager.h"
 #include "ios/chrome/browser/chrome_paths.h"
 #include "ios/chrome/browser/chrome_switches.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/first_run/first_run.h"
 #include "ios/chrome/browser/install_time_util.h"
 #include "ios/chrome/browser/ios_chrome_field_trials.h"
@@ skipping 252 matching lines @@
   bool result = http_header_provider->ForceVariationIds(
       command_line->GetSwitchValueASCII(switches::kIOSForceVariationIds),
       &variation_ids);
   CHECK(result) << "Invalid list of variation ids specified (either in --"
                 << switches::kIOSForceVariationIds << " or in chrome://flags)";
 
   feature_list->InitializeFromCommandLine(
       command_line->GetSwitchValueASCII(switches::kEnableIOSFeatures),
       command_line->GetSwitchValueASCII(switches::kDisableIOSFeatures));
 
+#if defined(FIELDTRIAL_TESTING_ENABLED)
+  if (!command_line->HasSwitch(
+          variations::switches::kDisableFieldTrialTestingConfig) &&
+      !command_line->HasSwitch(switches::kForceFieldTrials) &&
+      !command_line->HasSwitch(variations::switches::kVariationsServerURL)) {
+    variations::AssociateDefaultFieldTrialConfig(feature_list.get());
+  }
+#endif  // defined(FIELDTRIAL_TESTING_ENABLED)
+
   variations::VariationsService* variations_service =
       application_context_->GetVariationsService();
   if (variations_service)
     variations_service->CreateTrialsFromSeed(feature_list.get());
 
   base::FeatureList::SetInstance(std::move(feature_list));
 
   SetupIOSFieldTrials();
 }
 
 void IOSChromeMainParts::SetupMetrics() {
   metrics::MetricsService* metrics = application_context_->GetMetricsService();
   metrics->AddSyntheticTrialObserver(
       variations::VariationsHttpHeaderProvider::GetInstance());
   // Now that field trials have been created, initializes metrics recording.
   metrics->InitializeMetricsRecordingState();
 }
 
 void IOSChromeMainParts::StartMetricsRecording() {
   bool wifiOnly = local_state_->GetBoolean(prefs::kMetricsReportingWifiOnly);
   bool isConnectionCellular = net::NetworkChangeNotifier::IsConnectionCellular(
       net::NetworkChangeNotifier::GetConnectionType());
   bool mayUpload = !wifiOnly || !isConnectionCellular;
 
   application_context_->GetMetricsServicesManager()->UpdateUploadPermissions(
       mayUpload);
 }