[Smart Lock, Settings Reconciliation] Histograms for tracking initial pref values.

chrome/browser/password_manager/password_manager_setting_migrator_service.cc

Index: chrome/browser/password_manager/password_manager_setting_migrator_service.cc
diff --git a/chrome/browser/password_manager/password_manager_setting_migrator_service.cc b/chrome/browser/password_manager/password_manager_setting_migrator_service.cc
index 301b1367abeaa1edac95534be76ed55cad8e75f5..85e03f55195e89a2fea567e178997aebc3b55b7a 100644
--- a/chrome/browser/password_manager/password_manager_setting_migrator_service.cc
+++ b/chrome/browser/password_manager/password_manager_setting_migrator_service.cc
@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/prefs/pref_service_syncable_util.h"
 #include "chrome/browser/profiles/profile.h"
@@ -29,6 +30,9 @@ bool GetBooleanUserOrDefaultPrefValue(PrefService* prefs,
   return result;
 }
 
+const char kSettingsReconciliationInitialValuesMetrics[] =

[engedy, 2015/09/24 14:26:18]

nit: Inline this string literal.

It's customary for histograms, and allows the PRESUBMIT script to check that
there is a corresponding definition in histograms.xml (to prevent typos).

[melandory, 2015/09/28 07:10:12]

Done.

+    "PasswordManager.SettingsReconciliation.InitialValues";
+
 void ChangeOnePrefBecauseAnotherPrefHasChanged(
     PrefService* prefs,
     const std::string& other_pref_name,
@@ -60,6 +64,17 @@ void SaveCurrentPrefState(PrefService* prefs,
       prefs, password_manager::prefs::kPasswordManagerSavingEnabled);
 }
 
+PasswordManagerPreferencesInitialValues GetInitialValue(bool legacy_pref_value,
+                                                        bool new_pref_value) {
+  if (!new_pref_value && !legacy_pref_value)
+    return N0L0;
+  if (!new_pref_value && legacy_pref_value)
+    return N0L1;
+  if (new_pref_value && !legacy_pref_value)
+    return N1L0;
+  return N1L1;
+}
+
 }  // namespace
 
 // static
@@ -120,9 +135,11 @@ void PasswordManagerSettingMigratorService::Observe(
   DCHECK_EQ(chrome::NOTIFICATION_PROFILE_ADDED, type);
   SaveCurrentPrefState(profile_->GetPrefs(), &initial_new_pref_value_,
                        &initial_legacy_pref_value_);
+  UMA_HISTOGRAM_ENUMERATION(
+      kSettingsReconciliationInitialValuesMetrics,
+      GetInitialValue(initial_legacy_pref_value_, initial_new_pref_value_),
+      NUM_INITIAL_VALUES);
   if (!password_manager::IsSettingsMigrationActive()) {
-    // TODO(melandory) Add histogram which will log initial values for the both
-    // settings.
     return;
   }
   if (ProfileSyncServiceFactory::HasProfileSyncService(profile_))
@@ -230,4 +247,6 @@ void PasswordManagerSettingMigratorService::MigrateAfterModelAssociation(
       UpdatePreferencesValues(prefs, false);
     }
   }
+  // TODO(melandory) Add histogram which will log initial and final values for

[engedy, 2015/09/24 14:26:18]

nit: I'm not sure I understand this comment correctly. Initial values are
already logged. Do you mean a histogram that would capture the combination of 4
values here?

[melandory, 2015/09/28 07:10:12]

Yep.

+  // the both preferences.
 }