Adding client side field trial for sampling on non-stable channels.

chrome/browser/metrics/chrome_metrics_services_manager_client.cc

 // Copyright 2015 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/metrics/chrome_metrics_services_manager_client.h"
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/browser/metrics/chrome_metrics_service_client.h"
 #include "chrome/browser/metrics/variations/chrome_variations_service_client.h"
 #include "chrome/browser/metrics/variations/ui_string_overrider_factory.h"
 #include "chrome/browser/ui/browser_otr_state.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/installer/util/google_update_settings.h"
 #include "components/metrics/enabled_state_provider.h"
 #include "components/metrics/metrics_state_manager.h"
 #include "components/prefs/pref_service.h"
 #include "components/rappor/rappor_service.h"
 #include "components/variations/service/variations_service.h"
 #include "components/variations/variations_associated_data.h"
+#include "components/version_info/version_info.h"
 #include "content/public/browser/browser_thread.h"
 
 #if defined(OS_WIN)
 #include "base/win/registry.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/install_static/install_util.h"
 #include "chrome/installer/util/browser_distribution.h"
 #include "components/crash/content/app/crashpad.h"
 #endif  // OS_WIN
 
@@ skipping 73 matching lines @@
       local_state_(local_state) {
   DCHECK(local_state);
 
   SetupMetricsStateForChromeOS();
 }
 
 ChromeMetricsServicesManagerClient::~ChromeMetricsServicesManagerClient() {}
 
 // static
 void ChromeMetricsServicesManagerClient::CreateFallbackSamplingTrial(
+    version_info::Channel channel,
     base::FeatureList* feature_list) {
   // The trial name must be kept in sync with the server config controlling
   // sampling. If they don't match, then clients will be shuffled into different
   // groups when the server config takes over from the fallback trial.
   static const char kTrialName[] = "MetricsAndCrashSampling";
   scoped_refptr<base::FieldTrial> trial(
       base::FieldTrialList::FactoryGetFieldTrial(
           kTrialName, 1000, "Default", base::FieldTrialList::kNoExpirationYear,
           1, 1, base::FieldTrial::ONE_TIME_RANDOMIZED, nullptr));
 
+  // On all channels except stable, we sample out at a minimal rate to ensure
+  // the code paths are exercised in the wild before hitting stable.
+  int sampled_in_rate = 990;
+  int sampled_out_rate = 10;
+  if (channel == version_info::Channel::STABLE) {
+    sampled_in_rate = 100;
+    sampled_out_rate = 900;
+  }
+
   // Like the trial name, the order that these two groups are added to the trial
   // must be kept in sync with the order that they appear in the server config.
 
   // 100 per-mille sampling rate group.
   static const char kInSampleGroup[] = "InReportingSample";
-  AppendSamplingTrialGroup(kInSampleGroup, 100, trial.get());
+  AppendSamplingTrialGroup(kInSampleGroup, sampled_in_rate, trial.get());
 
   // 900 per-mille sampled out.
   static const char kSampledOutGroup[] = "OutOfReportingSample";
-  AppendSamplingTrialGroup(kSampledOutGroup, 900, trial.get());
+  AppendSamplingTrialGroup(kSampledOutGroup, sampled_out_rate, trial.get());
 
   // Setup the feature.
   const std::string& group_name = trial->GetGroupNameWithoutActivation();
   feature_list->RegisterFieldTrialOverride(
       kMetricsReportingFeature.name,
       group_name == kSampledOutGroup
           ? base::FeatureList::OVERRIDE_DISABLE_FEATURE
           : base::FeatureList::OVERRIDE_ENABLE_FEATURE,
       trial.get());
 }
@@ skipping 113 matching lines @@
 ChromeMetricsServicesManagerClient::GetMetricsStateManager() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!metrics_state_manager_) {
     metrics_state_manager_ = metrics::MetricsStateManager::Create(
         local_state_, enabled_state_provider_.get(),
         base::Bind(&PostStoreMetricsClientInfo),
         base::Bind(&GoogleUpdateSettings::LoadMetricsClientInfo));
   }
   return metrics_state_manager_.get();
 }