Cleanup: Pass std::string as const reference from tools/clang/

tools/clang/empty_string/tests/test-original.cc

Index: tools/clang/empty_string/tests/test-original.cc
diff --git a/tools/clang/empty_string/tests/test-original.cc b/tools/clang/empty_string/tests/test-original.cc
index 2edb896cc631665ed77a51e5a2c62c5644011986..2375e8972e4c680e8604254bf36a774ab2d0a149 100644
--- a/tools/clang/empty_string/tests/test-original.cc
+++ b/tools/clang/empty_string/tests/test-original.cc
@@ -32,14 +32,14 @@ class TestInitializers {
 
 // Tests for temporary std::strings.
 void TestTemporaries(const std::string& reference_argument,
-                     const std::string value_argument) {
+                     const std::string& value_argument) {

[hans, 2016/05/25 17:31:25]

This file is a test case for the plugin, it's not actually code that we run, so
it shouldn't be changed.

Also note that the name of this parameter suggests it should be passed by value
rather than reference :-)

[ki.stfu, 2016/05/25 17:37:58]

Thanks for very quick response!

   TestTemporaries("", "");
   TestTemporaries(std::string(""), std::string(""));
 }
 
 // Tests for temporary std::wstrings.
 void TestWideTemporaries(const std::wstring& reference_argument,
-                         const std::wstring value_argument) {
+                         const std::wstring& value_argument) {
   TestWideTemporaries(L"", L"");
   TestWideTemporaries(std::wstring(L""), std::wstring(L""));
 }