Mojo: Add a threaded perf test for (local) message pipes.

mojo/public/tests/test_support.h

Index: mojo/public/tests/test_support.h
diff --git a/mojo/public/tests/test_support.h b/mojo/public/tests/test_support.h
index 32a54c9646468eb557f51919ec9b60e411daa82f..e259456c2c8429e75155def9c4ed092305776e94 100644
--- a/mojo/public/tests/test_support.h
+++ b/mojo/public/tests/test_support.h
@@ -22,4 +22,18 @@ MOJO_TEST_SUPPORT_EXPORT void MojoTestSupportLogPerfResult(
 }  // extern "C"
 #endif
 
+#ifdef __cplusplus
+namespace mojo {
+namespace test {
+
+inline void LogPerfResult(const char* test_name,
+                          double value,
+                          const char* units) {
+  MojoTestSupportLogPerfResult(test_name, value, units);
+}
+
+}  // namespace test
+}  // namespace mojo
+#endif  // __cplusplus
+
 #endif  // MOJO_PUBLIC_TESTS_TEST_SUPPORT_H_