appease clang-tidy

.clang_complete

@@ -4,6 +4,7 @@
 -Igens
 -Iinclude
 -Isrc/core/ext/upb-generated
+-Isrc/core/ext/upbdefs-generated
 -Ithird_party/abseil-cpp
 -Ithird_party/address_sorting/include
 -Ithird_party/benchmark/include

src/core/ext/xds/xds_api.cc

@@ -312,9 +312,11 @@ enum MatchType {
 };
 
 // Returns true if match succeeds.
-bool DomainMatch(MatchType match_type, std::string domain_pattern,
+bool DomainMatch(MatchType match_type, const std::string& domain_pattern_in,
-                 std::string expected_host_name) {
+                 const std::string& expected_host_name_in) {
   // Normalize the args to lower-case. Domain matching is case-insensitive.
+  std::string domain_pattern = domain_pattern_in;
+  std::string expected_host_name = expected_host_name_in;
   std::transform(domain_pattern.begin(), domain_pattern.end(),
                  domain_pattern.begin(),
                  [](unsigned char c) { return std::tolower(c); });