Fix ScopedTestNSSDB for older NSS versions.

crypto/scoped_test_nss_db.cc

Index: crypto/scoped_test_nss_db.cc
diff --git a/crypto/scoped_test_nss_db.cc b/crypto/scoped_test_nss_db.cc
index a3ff68b8b16dd2506f75f2f379c3a431b5e92575..452c26d73e50500dd820b58f3821387404414448 100644
--- a/crypto/scoped_test_nss_db.cc
+++ b/crypto/scoped_test_nss_db.cc
@@ -29,17 +29,22 @@ ScopedTestNSSDB::~ScopedTestNSSDB() {
   // Don't close when NSS is < 3.15.1, because it would require an additional
   // sleep for 1 second after closing the database, due to
   // http://bugzil.la/875601.
-  if (!NSS_VersionCheck("3.15.1") || !slot_)
+  if (!NSS_VersionCheck("3.15.1")) {
+    LOG(ERROR) << "NSS version is < 3.15.1, test DB will not be closed.";
+    temp_dir_.Take();
     return;
+  }
 
   // NSS is allowed to do IO on the current thread since dispatching
   // to a dedicated thread would still have the affect of blocking
   // the current thread, due to NSS's internal locking requirements
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
-  SECStatus status = SECMOD_CloseUserDB(slot_.get());
-  if (status != SECSuccess)
-    PLOG(ERROR) << "SECMOD_CloseUserDB failed: " << PORT_GetError();
+  if (slot_) {
+    SECStatus status = SECMOD_CloseUserDB(slot_.get());
+    if (status != SECSuccess)
+      PLOG(ERROR) << "SECMOD_CloseUserDB failed: " << PORT_GetError();
+  }
 
   if (!temp_dir_.Delete())
     LOG(ERROR) << "Could not delete temporary directory.";