Make VariationsService simulate received seeds.

chrome/browser/metrics/variations/variations_service.cc

 // Copyright (c) 2012 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/variations/variations_service.h"
 
 #include <set>
 
 #include "base/build_time.h"
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
+#include "base/timer/elapsed_timer.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/network_time/network_time_tracker.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_prefs/pref_registry_syncable.h"
 #include "components/variations/proto/variations_seed.pb.h"
 #include "components/variations/variations_seed_processor.h"
+#include "components/variations/variations_seed_simulator.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/url_util.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "net/http/http_util.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
@@ skipping 341 matching lines @@
     time_since_last_fetch = now - last_request_started_time_;
   UMA_HISTOGRAM_CUSTOM_COUNTS("Variations.TimeSinceLastFetchAttempt",
                               time_since_last_fetch.InMinutes(), 0,
                               base::TimeDelta::FromDays(7).InMinutes(), 50);
   last_request_started_time_ = now;
 }
 
 void VariationsService::StoreSeed(const std::string& seed_data,
                                   const std::string& seed_signature,
                                   const base::Time& date_fetched) {
-  if (!seed_store_.StoreSeedData(seed_data, seed_signature, date_fetched))
+  VariationsSeed seed;
+  if (!seed_store_.StoreSeedData(seed_data, seed_signature, date_fetched,
+                                 &seed)) {
     return;
+  }
   RecordLastFetchTime();
+
+  const base::ElapsedTimer timer;
+
+  // TODO(asvitkine): Get the version that will be used on restart instead of
+  // the current version (i.e. if an update has been downloaded).
+  const chrome::VersionInfo current_version_info;
+  if (!current_version_info.is_valid())
+    return;
+
+  const base::Version current_version(current_version_info.Version());
+  if (!current_version.IsValid())
+    return;
+
+  const base::FieldTrial::EntropyProvider* entropy_provider =
+      base::FieldTrialList::GetEntropyProviderForOneTimeRandomization();
+  // One-time randomization should be supported by the global FieldTrialList in
+  // the process the VariationService is running in, so |entropy_provider| must
+  // be non-NULL.
+  DCHECK(entropy_provider);
+  VariationsSeedSimulator seed_simulator(*entropy_provider);
+
+  VariationsSeedSimulator::Result result = seed_simulator.SimulateSeedStudies(
+      seed, g_browser_process->GetApplicationLocale(),
+      GetReferenceDateForExpiryChecks(local_state_), current_version,
+      GetChannelForVariations(), GetCurrentFormFactor());
+
+  UMA_HISTOGRAM_COUNTS_100("Variations.SimulateSeed.NormalChanges",
+                           result.normal_group_change_count);
+  UMA_HISTOGRAM_COUNTS_100("Variations.SimulateSeed.KillBestEffortChanges",
+                           result.kill_best_effort_group_change_count);
+  UMA_HISTOGRAM_COUNTS_100("Variations.SimulateSeed.KillCriticalChanges",
+                           result.kill_critical_group_change_count);
+
+  UMA_HISTOGRAM_TIMES("Variations.SimulateSeed.Duration", timer.Elapsed());
 }
 
 void VariationsService::FetchVariationsSeed() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   const ResourceRequestAllowedNotifier::State state =
       resource_request_allowed_notifier_->GetResourceRequestsAllowedState();
   RecordRequestsAllowedHistogram(ResourceRequestStateToHistogramValue(state));
   if (state != ResourceRequestAllowedNotifier::ALLOWED) {
     DVLOG(1) << "Resource requests were not allowed. Waiting for notification.";
@@ skipping 89 matching lines @@
 
 void VariationsService::RecordLastFetchTime() {
   // local_state_ is NULL in tests, so check it first.
   if (local_state_) {
     local_state_->SetInt64(prefs::kVariationsLastFetchTime,
                            base::Time::Now().ToInternalValue());
   }
 }
 
 }  // namespace chrome_variations