Implement ScopedTestNSSDB instead of OpenTestNSSDB()

crypto/nss_util.h

Index: crypto/nss_util.h
diff --git a/crypto/nss_util.h b/crypto/nss_util.h
index 88d7d052fa89d7b1bbebf18de733b4a0f64d73ca..9e09d6db47eb390c2246ed2f3c81d13f3820bab8 100644
--- a/crypto/nss_util.h
+++ b/crypto/nss_util.h
@@ -128,11 +128,21 @@ CRYPTO_EXPORT int64 BaseTimeToPRTime(base::Time time);
 
 #if defined(USE_NSS)
 // Exposed for unittests only.
-// TODO(mattm): when https://bugzilla.mozilla.org/show_bug.cgi?id=588269 is
-// fixed, switch back to using a separate userdb for each test.  (Maybe refactor
-// to provide a ScopedTestNSSDB instead of open/close methods.)
-CRYPTO_EXPORT bool OpenTestNSSDB();
-// NOTE: due to NSS bug 588269, mentioned above, there is no CloseTestNSSDB.
+// TODO(mattm): When NSS 3.14 is the minimum version required,
+// switch back to using a separate user DB for each test.
+// Because of https://bugzilla.mozilla.org/show_bug.cgi?id=588269 , the
+// opened user DB is not automatically closed.
+class CRYPTO_EXPORT_PRIVATE ScopedTestNSSDB {
+ public:
+  ScopedTestNSSDB();
+  ~ScopedTestNSSDB();
+
+  bool is_open() { return is_open_; }
+
+ private:
+  bool is_open_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedTestNSSDB);
+};
 
 // NSS has a bug which can cause a deadlock or stall in some cases when writing
 // to the certDB and keyDB. It also has a bug which causes concurrent key pair