Convert PrefHashFilter enums to enum class.

components/user_prefs/tracked/mock_validation_delegate.cc

Index: components/user_prefs/tracked/mock_validation_delegate.cc
diff --git a/components/user_prefs/tracked/mock_validation_delegate.cc b/components/user_prefs/tracked/mock_validation_delegate.cc
index 4362f9911a46324c7805b5cbd079209a7edbe6cc..c82deb50a5f3cc981cc69895fb967f10768f7895 100644
--- a/components/user_prefs/tracked/mock_validation_delegate.cc
+++ b/components/user_prefs/tracked/mock_validation_delegate.cc
@@ -63,7 +63,7 @@ void MockValidationDelegate::OnAtomicPreferenceValidation(
     bool is_personal) {
   record_->RecordValidation(pref_path, value_state,
                             external_validation_value_state, is_personal,
-                            PrefHashFilter::TRACKING_STRATEGY_ATOMIC);
+                            PrefHashFilter::PrefTrackingStrategy::ATOMIC);
 }
 
 void MockValidationDelegate::OnSplitPreferenceValidation(
@@ -75,5 +75,5 @@ void MockValidationDelegate::OnSplitPreferenceValidation(
     bool is_personal) {
   record_->RecordValidation(pref_path, value_state,
                             external_validation_value_state, is_personal,
-                            PrefHashFilter::TRACKING_STRATEGY_SPLIT);
+                            PrefHashFilter::PrefTrackingStrategy::SPLIT);
 }