Resetting metrics ids on clump detection.

chrome/browser/metrics/metrics_service.cc

Index: chrome/browser/metrics/metrics_service.cc
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index a313c4514051b636009db4616c10559f98a64ca5..5ec323faf87fa35ba4af1267b6937a368372de50 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -521,7 +521,8 @@ void MetricsService::DiscardOldStabilityStats(PrefService* local_state) {
 }
 
 MetricsService::MetricsService()
-    : recording_active_(false),
+    : variations_state_initialized_(false),
+      recording_active_(false),
       reporting_active_(false),
       test_mode_active_(false),
       state_(INITIALIZED),
@@ -558,6 +559,21 @@ void MetricsService::InitializeMetricsRecordingState(
   scheduler_.reset(new MetricsReportingScheduler(callback));
 }
 
+void MetricsService::InitializeVariationsState(bool recording_enabled) {
+  if (!variations_state_initialized_) {
+    variations_state_initialized_ = true;
+
+    if (g_browser_process->local_state()->GetBoolean(
+        prefs::kMetricsCloneDetected))
+      ResetVariationsState();
+  }
+
+  GetLowEntropySource();
+
+  if (recording_enabled)

[Alexei Svitkine (slow), 2014/03/28 15:00:17]

Hmm, this requires the caller to know this, which we don't from
GetLowEntropySource()...

Let's go with ResetMetricsIDsIfNecessary() instead and call it from both places
and a have a bool to guard if we did the check already.

[jwd, 2014/03/28 16:23:50]

Done.

+    ForceClientIdCreation();
+}
+
 void MetricsService::Start() {
   HandleIdleSinceLastTransmission(false);
   EnableRecording();
@@ -633,6 +649,7 @@ MetricsService::CreateEntropyProvider(ReportingState reporting_state) {
 void MetricsService::ForceClientIdCreation() {
   if (!client_id_.empty())
     return;
+
   PrefService* pref = g_browser_process->local_state();
   client_id_ = pref->GetString(prefs::kMetricsClientID);
   if (!client_id_.empty())
@@ -1192,6 +1209,8 @@ int MetricsService::GetLowEntropySource() {
   if (low_entropy_source_ != kLowEntropySourceNotSet)
     return low_entropy_source_;
 
+  ResetVariationsState();

[Alexei Svitkine (slow), 2014/03/28 15:00:17]

Why is this called from here? Did you mean Initialize instead?

[jwd, 2014/03/28 16:23:50]

Done.

+
   PrefService* local_state = g_browser_process->local_state();
   const CommandLine* command_line(CommandLine::ForCurrentProcess());
   // Only try to load the value from prefs if the user did not request a reset.
@@ -1862,6 +1881,7 @@ void MetricsService::RegisterSyntheticFieldTrial(
 }
 
 void MetricsService::CheckForClonedInstall() {
+  DVLOG(2) << "\n\nChecking for cloned installs\n\n";
   DCHECK(!cloned_install_detector_);
 
   metrics::MachineIdProvider* provider =
@@ -1876,6 +1896,19 @@ void MetricsService::CheckForClonedInstall() {
   cloned_install_detector_->CheckForClonedInstall(local_state);
 }
 
+void MetricsService::ResetVariationsState() {
+  PrefService* local_state = g_browser_process->local_state();
+  DCHECK(local_state->GetBoolean(prefs::kMetricsCloneDetected));
+  DCHECK(client_id_.empty());
+  DCHECK(low_entropy_source_ == kLowEntropySourceNotSet);
+
+  DVLOG(2) << "\n\nresetting variatinos state\n\n";
+
+  local_state->ClearPref(prefs::kMetricsClientID);
+  local_state->ClearPref(prefs::kMetricsLowEntropySource);
+  local_state->SetBoolean(prefs::kMetricsCloneDetected, false);
+}
+
 void MetricsService::GetCurrentSyntheticFieldTrials(
     std::vector<chrome_variations::ActiveGroupId>* synthetic_trials) {
   DCHECK(synthetic_trials);