Address minor comments on https://codereview.chromium.org/2816033002

components/password_manager/core/browser/psl_matching_helper.h

Index: components/password_manager/core/browser/psl_matching_helper.h
diff --git a/components/password_manager/core/browser/psl_matching_helper.h b/components/password_manager/core/browser/psl_matching_helper.h
index 7bfea29daa9ed4515f88adcb8dd1d9b3a1a8cf25..ed10f3074dde0197fe99b93e7d34650b0173d037 100644
--- a/components/password_manager/core/browser/psl_matching_helper.h
+++ b/components/password_manager/core/browser/psl_matching_helper.h
@@ -36,6 +36,8 @@ enum class MatchResult {
 #if defined(UNIT_TEST)
 std::ostream& operator<<(std::ostream& out, MatchResult result);
 
+// These functions are used in production internally but exposed for testing.
+
 // Returns true iff |form_signon_realm| designates a federated credential for
 // |origin|. It doesn't check the port because |form_signon_realm| doesn't have
 // it.