Use the USE_NSS macro to help porting to FreeBSD, OpenBSD, etc....

base/test/test_suite.h

Index: base/test/test_suite.h
===================================================================
--- base/test/test_suite.h	(revision 37224)
+++ base/test/test_suite.h	(working copy)
@@ -212,13 +212,13 @@
 
     icu_util::Initialize();
 
-#if defined(OS_POSIX) && !defined(OS_MACOSX)
+#if defined(USE_NSS)
     // Trying to repeatedly initialize and cleanup NSS and NSPR may result in
     // a deadlock. Such repeated initialization will happen when using test
     // isolation. Prevent problems by initializing NSS here, so that the cleanup
     // will be done only on process exit.
     base::EnsureNSSInit();
-#endif  // defined(OS_POSIX) && !defined(OS_MACOSX)
+#endif  // defined(USE_NSS)
   }
 
   virtual void Shutdown() {