Send a TrackedPreference incident when registry pref validation fails.

components/user_prefs/tracked/tracked_atomic_preference.cc

Index: components/user_prefs/tracked/tracked_atomic_preference.cc
diff --git a/components/user_prefs/tracked/tracked_atomic_preference.cc b/components/user_prefs/tracked/tracked_atomic_preference.cc
index 2415d7f844a909a3ebbdcbd70741b05c8dff52ae..e2b76784b81a7be1685d390f92c06d2be5dbe4c8 100644
--- a/components/user_prefs/tracked/tracked_atomic_preference.cc
+++ b/components/user_prefs/tracked/tracked_atomic_preference.cc
@@ -45,19 +45,18 @@ bool TrackedAtomicPreference::EnforceAndReport(
   helper_.ReportValidationResult(value_state, transaction->GetStoreUMASuffix());
 
   PrefHashStoreTransaction::ValueState external_validation_value_state =
-      PrefHashStoreTransaction::UNCHANGED;
+      PrefHashStoreTransaction::UNSUPPORTED;
   if (external_validation_transaction) {
     external_validation_value_state =
         external_validation_transaction->CheckValue(pref_path_, value);
     helper_.ReportValidationResult(
         external_validation_value_state,
         external_validation_transaction->GetStoreUMASuffix());
-
-    // TODO(proberge): Call delegate_->OnAtomicPreferenceValidation.
   }
 
   if (delegate_) {
     delegate_->OnAtomicPreferenceValidation(pref_path_, value, value_state,
+                                            external_validation_value_state,
                                             helper_.IsPersonal());
   }
   TrackedPreferenceHelper::ResetAction reset_action =