Split the NullInitialized signal out of TrustedInitialized.

chrome/browser/prefs/tracked/tracked_preference_helper.cc

Index: chrome/browser/prefs/tracked/tracked_preference_helper.cc
diff --git a/chrome/browser/prefs/tracked/tracked_preference_helper.cc b/chrome/browser/prefs/tracked/tracked_preference_helper.cc
index 90bc11f31c6765c65a7edb969ed84027fb2cf7c7..1da583f2094554a4c5b7b448d78a783c0e88b393 100644
--- a/chrome/browser/prefs/tracked/tracked_preference_helper.cc
+++ b/chrome/browser/prefs/tracked/tracked_preference_helper.cc
@@ -26,6 +26,7 @@ TrackedPreferenceHelper::ResetAction TrackedPreferenceHelper::GetAction(
     case PrefHashStoreTransaction::CLEARED:
       // Unfortunate case, but there is nothing we can do.
       return DONT_RESET;
+    case PrefHashStoreTransaction::TRUSTED_NULL_VALUE:  // Falls through.
     case PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE:
       // It is okay to seed the hash in this case.
       return DONT_RESET;
@@ -69,6 +70,10 @@ void TrackedPreferenceHelper::ReportValidationResult(
       UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceTrustedInitialized",
                                 reporting_id_, reporting_ids_count_);
       return;
+    case PrefHashStoreTransaction::TRUSTED_NULL_VALUE:
+      UMA_HISTOGRAM_ENUMERATION("Settings.TrackedPreferenceNullInitialized",
+                                reporting_id_, reporting_ids_count_);
+      return;
   }
   NOTREACHED() << "Unexpected PrefHashStoreTransaction::ValueState: "
                << value_state;